Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
SWP2703061
Hydraulic Analysis of Springbrook Creek FEMA Re -Mapping Study City of Renton June 2006 Hydraulic Analysis of Springbrook Creek FEMA Re -Mapping Study City of Renton June 2006 CERTIFICATE OF ENGINEER CITY OF RENTON HYDRAULIC ANALYSIS FOR SPRINGBROOK CREEK FEMA RE -MAPPING STUDY The technical material and data contained in this report were prepared under the supervision and direction of the undersigned, whose seal as a registered professional engineer licensed to practice as such in the State of Washington is affixed below. p, T R s C�� WtIf k?, 29741 SIONA I, t EXPIRES: 1 1— 0 7— v/ S • G't WA �r y 24D55 ,�A$' IONAL G1 EXPIRES: 1 Z-04— 0� f w Mary B. eber Project Manager R. W. Beck, Inc. r Mike S. Giseburt Project Manager R. W. Beck, Inc. RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Finahcerti6cate.doc 6/19/06 R. W. BECK Hydraulic Analysis for Springbrook Creek FEMA Re -Mapping Study Table of Contents Certificate of Engineer Table of Contents List of Tables, Figures, Exhibits, and Appendices EXECUTIVESUMMARY....................................................................................ES-1 Section 1 INTRODUCTION.....................................................................................1-1 Section 2 FEQ MODEL DEVELOPMENT............................................................2-1 2.1 Springbrook Creek Model Schematic .......................................................2-1 2.2 Boundary Conditions................................................................................2-2 2.3 Inflow Hydrographs..................................................................................2-7 2.4 Simulation Scenarios................................................................................2-8 2.5 Cross Section Validation..........................................................................2-9 2.6 Function Tables for FEQ Model.............................................................2-10 2.7 FEQ Model Validation...........................................................................2-35 2.8 Volume Comparison...............................................................................2-36 Section 3 FLOOD PROFILES..................................................................................3-1 Section 4 FLOODPLAIN MANAGEMENT APPLICATIONS ............................4-1 4.1 Floodplain Boundaries..............................................................................4-1 4.2 Floodway Boundaries...............................................................................4-1 Section 5 REFERENCES..........................................................................................5-1 This report has been prepared for the use of the client for the specific purposes identified in the report. The conclusions, observations and recommendations contained herein attributed to R. W. Beck, Inc. (R. W. Beck) constitute the opinions of R. W. Beck. To the extent that statements, information and opinions provided by the client or others have been used in the preparation of this report, R. W. Beck has relied upon the same to be accurate, and for which no assurances are intended and no representations or warranties are made. R. W. Beck makes no certification and gives no assurances except as explicitly set forth in this report. Copyright 2006, R. W. Beck, Inc. All rights reserved. R:\Seattle\l1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table of Contents List of Tables Base Flood Water Surface Elevation Comparison......................................................... 2 Table 1 BRPS Pump Capacity Data............................................................................ 2-2 Table 2 BRPS — Operation Unrestricted by Green River Flow ................................... 2-5 Table 3 BRPS - Assumed Operation Rules Restricted by Green River Flow.............2-6 Table 4 Input Hydrograph Identification.....................................................................2-7 Table 5 Cross Section and Floodplain Data..............................................................2-13 Table 6 Hydraulic Structure Data..............................................................................2-34 Table 7 FEQ Validation using the November 2001 Storm Event.............................2-36 Table 8 Simulated Water Surface Elevations 10-, 50-, and 100-year Floods ............. 3-2 Table 9 Simulated Peak Flows at Selected Locations 10-, 50-, and 100-Year Floods.............................................................................................................. 3-2 Table 10 Floodway Analysis Results..........................................................................4-2 List of Figures Figure 1 Major Drainage System Modeled by FEQ....................................................1-3 Figure 2 FEQ Model Schematic.................................................................................. 2-3 Exhibits Exhibit A — Flood Profiles Exhibit B — Floodplain and Floodway Boundary Map Appendices Appendix A — Hydrologic Analysis for Floodplain Mapping Study for Springbrook Creek, King County, Washington (NHC, October 25, 2005) and memorandum entitled "Review of Springbrook Creek HSPF Calibration and Gage Records", (NEC, October 25, 2005) Appendix B — Springbrook Creek FEMA Re -mapping Study — Cross Section Validation (September 16, 2003) and Field Reconnaissance Photographs Appendix C — Digital Appendix (includes flood profiles, floodway map, and computer models) Appendix D — Memorandum entitled "FEQ-HSPF Volume Comparison" (R.W. Beck, October 28, 2005) ii RASeatt1e\11-00781 Springbrook Creek FEMA remapping\ReporU\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 EXECUTIVE SUMMARY This memorandum documents the hydraulic methods and results performed for the floodplain re -mapping study of Springbrook Creek between the Black River Pump Station (BRPS) and SW 43`d Street (also referred to as South 1801h Street). SW 43`d Street is the approximate boundary line between the cities of Renton and Kent, Washington. The study reach is shown on FIRM numbers 53033CO976 F, 53033CO978 F, and 53033CO979 F revised May 16, 1995. On this map, the BRPS is labeled "P-1 Pumping Station." The hydraulic and hydrologic analyses for this project were conducted following the approach described in an earlier memorandum by Northwest Hydraulics, Inc (NHC). This approach was reviewed and approved by the FEMA Map Coordination Contractor in a letter to the City Renton, dated September 25, 2002. Continuous hydrologic simulation modeling for a 53 year period of record (October 1, 1948 through September 30, 2002) was used to identify and adjust storm inflow hydrographs to Springbrook Creek that correspond to recurrence intervals required for unsteady flow hydraulic modeling and subsequent floodplain mapping. Two types of potential flood generating peak events were identified for hydraulic analysis: a Storage Scenario, which includes events that produce very high water surface elevation at the Black River Pump Station due to pumping restrictions caused by high flows in the Green River, and a Conveyance Scenario which includes events that exhibit maximum peak flows into the pump station forebay. The hydrologic analysis (Hydrologic Analysis for F000dplain Mapping Study of Springbrook Creek, King County, Washington, NHC) was submitted to FEMA in November, 2003. FEMA provided review comments and the final hydrologic report was submitted on October 25, 2005 and accompanies this memorandum in Appendix A. Appendix A also includes a separate memorandum dated October 25, 2005 that was prepared to respond to FEMA questions with regards to hydrologic model clibration. The memorandum includes supplemental information comparing simulated flows versus gauged flows at several locations and concluded that the HSPF model is well calibrated. The hydraulic analysis used the flood events identified by the hydrologic analysis to analyze the Springbrook Creek system. An unsteady flow model was used to determine the base flood profile and the floodplain and floodway delineation. An unsteady flow model can simulate flood routing on the creek system more accurately than a steady state model because it accounts for the attenuation that occurs due to storage in the system. The Springbrook Creek system has a significant amount of storage due to adjacent wetlands, so using a model that has the ability to attenuate the peak flow through this storage was important in order to provide an accurate assessment of the water surface elevations along the creek. RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 EXECUTIVE SUMMARY The base flood water surface elevations resulting from this study are considerably lower, especially at the downstream end of the reach, than in the previous FEMA study of Springbrook Creek. The water surface elevations at the upstream end of the study reach are about the same. A summary of the results are shown in the following table. Base Flood Water Surface Elevation Comparison' Previous Study Cross Previous Study Base Current Study Cross Current Study Base Section' Flood Water Surface Section Flood Water Surface Elevation (feet)' Elevation (feet) A 18.58 4010 16.69 B 18.58 4014 16.69 C 18.58 4015 16.69 D 18.58 4016 16.69 E 18.58 4018 16.69 F 18.58 4019 16.69 G 18.58 2074 16.69 H 19.98 4028 ' 16.70 1 19.98 4021 16.70 J 19.98 4022 16.70 K 19.98 4025 16.71 L 19.98 4027 16.71 M 19.38 Between 9043 and 16.81 9052 N 19.58 9073 16.92 0 19.58 9082 17.07 P 20.18 9108 18.88 Q 20.58 9115 19.68 R 20.88 9114 19.84 S 20.98 2076 21.25 T 21.18 2081 21.37 Panther Creek Wetland 19.58 F13 19.76 North Panther Creek Wetland 19.58 F21 and F31 18.79 South I Elevations in NAVD 1988. To convert to NGVD 1929, subtract 3.58 feet. 2 From the Flood Insurance Study King County, Washington and Incorporated Areas, Revised November 8, 1999 The difference between the base flood water surface elevations is a result of several factors: ES-2 R. W. BeckR:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 EXECUTIVE SUMMARY ■ Conveyance Improvements. Several conveyance improvements constructed since the last FEMA study have reduced several hydraulic restrictions and help to lower water surface elevations. ■ Capacity at the Black River Pump Station. The capacity of the BRPS at the time of the prior hydrologic and hydraulic study was 875 cfs. The current capacity is approximately 2180 cfs. ■ Unsteady Flow Analysis. The previous FEMA study used a steady state model to evaluate the flood profiles along Springbrook Creek. With a steady state model, flows are input as a constant, and the model does not allow for attenuation of the peak as a storm is routed through the system. For a basin such as Springbrook Creek, which contains a considerable amount of storage, the attenuation can be significant. By accounting for the flow attenuation, the unsteady model resulted in lower flows in the downstream end of the study reach, and therefore, the corresponding base flood water surface elevations are lower in this area. ■ Updated Channel Cross Section Data and Topographic Mapping. The current FEMA study incorporates new topographic mapping data used to provide information on the floodplain as well as new field survey of channel cross sections. While the base flood elevations were determined to be lower than the prior FEMA study, the extents of the floodway generally increased. The primary areas where the floodway was expanded were to include several wetlands within the study reach. Most of these wetlands are owned by the City of Renton. It was necessary to include wetlands as floodway because filling them would eliminate substantial storage and cause greater than a 1-foot rise in the base flood. The need to include the wetland storage in the floodway is most easily illustrated under the storage scenario. Under this scenario, the BRPS must restrict pumping rates in accordance with the Pump Operations and Procedures Plan (Green River Basin Program, 1986). The BRPS is required to reduce pumping rates when the Green River reaches flows in excess of 9,000 cfs at the Auburn gaging station and may have to completely cease pumping when the flows reach 12,000 cfs. During key periods of the simulated storage event, the BRPS would have to reduce pumping rates and then shut down for a four hour period. During the four-hour period with no outlet, the simulation shows that water in the system would back up and be stored in the creek and wetlands. Filling in the floodplain and wetlands would eliminate storage volume to hold this ponded volume and would translate into increased water levels in the lower portion of the system. Thus, the approach to mapping the floodway for this study was to focus on maintaining a majority of the floodplain, and in particular the valley wetlands, as floodway. Figure 1 schematically shows the wetland areas. The wetlands that were selected to be included in the floodway are 11 a, 11 b and 11 (the Panther Creek wetlands), and 4, 6, 7a and 7b. It should also be noted that the creek has apparently widened some since the previous study such that there were several locations where the previous floodway designation is located within the current active channel. At these locations the floodway was widened in order to span the active channel. RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA FitWl SpringbrookHydraulicsFinal.doc8/9/06R. W. Beck ES-3 Section 1 INTRODUCTION Springbrook Creek drains a basin of approximately 25 square miles located in a highly urbanized area of western King County, Washington (see Figure 1 of Appendix A). The basin is bounded on the west by the Green River levee system and on the east by uplands of the Soos Creek basin. The creek drains portions of the cities of Kent, Renton, Tukwila and unincorporated King County; however, Kent to the south and Renton to the north are by far the largest areas within the basin. Additional basin information can be found in Hydrologic Analysis for Floodplain Mapping Study of Springbrook Creek, King County, Washington (NHC, February 2004) in Appendix A. This study is referred to as the HASC in the memorandum. This technical memorandum documents the hydraulic analysis conducted for purposes of revising the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) of Springbrook Creek from the Black River Pump Station (BRPS) upstream to SW 43`d Street, Renton, Washington. The hydraulic analysis was conducted using flow events as defined in HASC. The existing Renton Valley surface water conveyance system is illustrated on Figure 1 of this document. The dominant drainage system in the valley is Springbrook Creek, which extends north from the City of Kent to the BRPS. Tributary to Springbrook Creek are Mill and Garrison creeks (Kent), Panther Creek and Rolling Hills Creek. These streams originate on the plateau on the east side of the Green River Valley and are supplemented by localized inflow within the valley. The Springbrook Creek portion of the study reach starts a SW 43`d Street and continues northeast through to the Oakesdale Business Park and through a recently added large box culvert under the Oakesdale Business Park access road followed immediately by the Oakesdale Avenue SW multiple parallel culvert crossing. After the Oakesdale Avenue SW culvert crossing, Springbrook Creek heads north and under a railroad bridge and then northeast towards the SW 341h Street culvert crossing which consists of a multiple parallel culverts. From SW 341h Street, the creek continues north to the recently constructed large box culvert at SW 271h Street. The creek then continues north to a private bridge just north of SW 271h Street and the confluence with the SW 23`d Street drainage channel, formerly known as the P-9 channel. From the SW 23`d Street drainage channel channel, the creek continues in a generally northerly direction to a private bridge for the access road to the Hunter Douglas site, then to the recently constructed Oakesdale Avenue SW bridge followed by the SW 161h Street bridge. Downstream of the SW 161h Street, the creek splits into two separate parallel channels that reconnect just upstream of Grady Way. The channel to the east was constructed in the early 1990s as part of the City's "Connecting Channel Project" to supplement the conveyance of the existing channel. The constructed channel crosses I-405 via a large box culvert. The existing channel to the west crosses R:\Seattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Sectionl under I-405 via a bridge. Immediately upstream of SW Grady Way, the two channels rejoin and cross under SW Grady Way via multiple parallel box culverts. From SW Grady Way, Springbrook Creek continues north to a bridge at SW 71h Street and then another bridge at Oakesdale Avenue SW. Downstream of the Oakesdale Avenue SW bridge crossing, the creek enters the forebay for the BRPS. The BRPS pumps Springbrook Creek to a wide channel that drains into the Green River. The SW 23`d Street drainage channel originates at the Panther Creek Wetland. The Panther Creek Wetland extends along the east side of SR 167 from about I-405 on the north to Panther Creek on the south near S 37th Street. The primary outlet from the Panther Creek Wetland is through a fish ladder structure that connects to a culvert that conveys flow west under SR 167 to the SW 23`d Street drainage channel. The SW 23`d Street drainage continues west to Springbrook Creek. Prior to joining Springbrook Creek it crosses several roads including SR 167, East Valley Road, and Lind Avenue SW. In addition, it passes through a culvert crossing under a utility corridor for the Olympic Pipeline Company. This culvert is located just west of Lind Avenue SW. Rolling Hills Creek is routed under I405 via a parallel pipe system and discharges a channel that flows south along the east side of SR 167. The channel enters a box culvert that conveys flow west across SR 167. This culvert connects to a pipe system along SW 191h Street which conveys flow west until it discharges into Springbrook Creek. During high flow periods this channel can overtop and spill out into the Panther Creek Wetland. The water surface elevations -in study reach are impacted by flood flows, storage capacity of the adjacent wetlands, the conveyance capacity of the multiple culverts and bridges and the operation of the BRPS. The operation of the BRPS depends on the flow in the Green River. An unsteady flow (hydrodynamic) hydraulic modeling was used to characterize water surface profiles in Springbrook Creek in order to account for dynamic flood storage in study reach wetlands and, more significantly, to accurately simulate flood discharges from Springbrook Creek to the Green River via the BRPS. Pump Station operations, including limitations on pumped discharges when Green River flows are high, impose a dynamic downstream boundary condition of the Springbrook Creek drainage system. The methodology is described in detail in the FEQ Model Development Section. 1-2 R. W. Beck RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doe 8/9/06 <~n c~n a SMITHERS gg�h P� SE a P5 CIDAV S 9�BaT N P4 L�p� RD S -lIHM � � z I h'p �P � o cn Z 11 SHATTUCK SHATTUCK M � Of � s cn DN\As A N � TALBOT CREST DR REEK WETLAND ¢ N 11 b PANTHER C P\N\ER Pv ? 1 N S LAKE P� R S16 O� a - Z 67 36" CD u " 36" E VALLEY RD 18 E VALLEY P�p�E ; RD S10 �qp N o N co N / a co S8 c~n in N VX �"� c/) 48 v) S \I I 05 LIND AV S 60" LIND --- r -ti -c o � S9b GO � N S13 4 6* N I 1. I N SCALE 1"=1000' 3� THOMAS AV SW S12 S7b 6 Q� N N S14 ���.� 5 � 7a S6 S9a cn POWELL AV SW M �--� cn sr a 7b* a Lo s 60" 15 54" cn R\NGB�pp�i yp N OAKESDALE V SW SP p,NN o� a 12 36 o 7c ` o S9c _ LONGACRES S7a RACE TRACK S11 3it S4 PSFB S17 S5 � JA KS N SW \ / RE PU P STATION RR R HYDRAULIC ANALYSIS FOR FLOOD PLAIN BLA RR MAPPING STUDY OF SPRINGBROOK CREEK RIVER WEST VALLEY HWY PUMP EYANCE M MODELED FIGURE 1 STATION ' ' �\ 4 ETLAND NUMBEFF MAJOR A MODESYSTEMAINAGE LED BY FEO APPROXIMATE SUB IN FVVMTO �—���� � R\�-� I PANTHER CREEK 5 � THESE WETLANDS ARE MODELED AS PART OF THE CREEK CROSS SECTION Section 2 FEQ MODEL DEVELOPMENT Springbrook Creek was modeled using the one-dimensional unsteady flow computer program Full Equations Model (FEQ) developed by Dr. Delbert Franz. FEQ simulates the complex hydraulics of the Springbrook Creek system by solving the full energy equation plus continuity integrated in both time and distance along the channel. The program separates flow into two broad classes: (1) stream reaches (branches), (2) level -pool reservoirs. These two parts are then combined using different control structures, such as junctions, bridges, culverts, weirs and others. The hydraulic characteristics of branches, level -pool reservoirs, and control structures are stored in function tables. The function tables are generally computed by using FEQUTL. The FEQ model used for this re -mapping study was originally developed for the Eastside Green River Watershed Project (R. W. Beck, Inc, 1996) for the City of Renton and was prepared using version 4.68. As part of the current re -mapping study, the model was updated to Version 10.03. FEQUTL is a utility program that aids in developing input into FEQ. FEQ model input files and model output are included in a digital appendix, Appendix C: Appendix C also includes FEQUTL files as well as a summary table listing all the FEQUTL files, their files names and their application in the FEQ model. The FEQ model was developed referencing NVGD 1929 vertical datum. The City's recent topographic mapping (1999) is in NAVD 1988 vertical datum. The floodplain mapping done as part of this study is all in NAVD 1988 vertical datum. Because it would require extensive effort to change the datum in the original FEQ model, it was decided to continue all hydraulic modeling in NGVD 1929 and use a datum conversion for the floodplain mapping. To convert elevations to NAVD 1988 vertical datum, 3.58 feet must be added. 2.1 Springbrook Creek Model Schematic A schematic of the Springbrook Creek system and the FEQ model is shown on Figure 2. The model extends from the BRPS on the north side and just upstream of the confluence of Mill and Springbrook creeks to the south. It also includes the SW 23rd Street draina a channel and the Panther Creek wetland, as well as the pipe systems along SW 19 and SW 34`h streets. The model was originally developed in 1996, but was updated in 2000 and 2001 to account for changes in infrastructure and to include newly surveyed cross sections (W&H Pacific, 1999) between SW 1601 Street and 27`h Avenue SW. These changes are documented in Springbrook Creek Channel and Habitat Improvement Project Technical Memorandum Hydraulic Analysis (R. W. Beck Inc, 2000) and Springbrook R:\Seaule\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Section 2 Creek Channel and Habitat Improvement Project Technical Memorandum Hydraulic Analysis — Supplemental (R. W. Beck Inc, 2001). In addition to the updates in 2000 and 2001, the model was updated to reflect another recent improvement. This improvement included the removal of a berm between two wetlands (7a and 7b) that were previously connected by a culvert. 2.2 Boundary Conditions The BRPS is the downstream boundary for the Springbrook Creek FEQ model. The operation of the pump station is dictated by the terms of the Pump Operations and Procedures Plan (POPP, Green River Basin Program, 1986), the Green River Interlocal Agreement (GRIA, Green River Basin Program, 1992) and the pump station operation manual (USDA SCS, 1972). These documents specify pumping rates for various forebay water levels, as well as limits on the maximum allowable pumped discharge when flows in the Green River are high. The BRPS is required to reduce pumping rates when the Green River reaches flows in excess of 9,000 cfs at the Auburn gaging station and may have to completely cease pumping when the flows reach 12,000 cfs. The most in depth analysis of the BRPS operating rules was documented in a May 22, 1995 memorandum to the City of Renton from Northwest Hydraulic Consultants. This memorandum provided the basis for BRPS simulation assumptions for the subsequent FEQ modeling in the 1996 effort. These simulation assumptions considered the regulatory limits on pumping (POPP, GRIA, etc.) as well as individual pump performance that considered pump curves, anticipated heads that the pumps would be operating under, and actual field pump tests for some of the larger pumps. Table 1 presents the BRPS pump capacity data. Modeled discharges assumed a fixed dynamic head consistent with the expected average forebay and Green River stages. Table 1 BRPS Pump Capacity Data' Pump Number Size Type Nominal Capacity (cfs) Modeled Discharge (cfs)(Z) Last Test Date P1 Small Electric 75 70 Not Tested P2 Medium Diesel 150 135 Not Tested P3 Large Diesel 514 480 Dec. 1,1994 P4 Medium Diesel 150 135 Not Tested P5 Large Diesel 514 (3) Not Tested P6 Large Diesel 514 480 Jan. 30, 1992 P7 Large Diesel 514 Not Operational Not Tested P8 Large Diesel 514 400 Dec. 29, 1994 ' Source: 1995 Memorandum to City of Renton from Northwest Hydraulic Consultants. 2 Modeled discharge rates are based on pump performance curves, anticipated static head, and pump test results 3 Prior to 1995, P5 was not operational. It has since been made operational. 2-2 R. W. BeckR:\Seatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doe 8/9/06 `� �� ` r LIY i= =WiRnz, ~ i L--J}(l t i ' tt\a cn S�if�'iid0 Z , icam j � �`,�``'(``�� '�' � .�J nfh �i'v �� h �` i I:\VAA\VAA025'36 1 �lCEP•alEfi`� 3ti�;=-.�------•�l"""'� AV S. /�?� t✓ P E�EE�E � _ V:::______,f � 7r-, x; �V c K 7 r! e�. }:✓ ., \` �".^✓ 1�1.' '' :C� r,t 1 _ �\ al r� i OVERFLOW--,,_ f aVALLEY} 54 � :�_ }qE ----- , �p �a (� £ `.../' Cf?1 ,,,,�1-,,.• ;� '`�i �t esµ ���f7�Q7.4� I`� of`wy' .r•� GENERAL ` `�� �-•-- --�. TAL80T CREST DR fE ��{ WILAND � sa ;��� HOSP! TAL , T ; f pAN� R W11 _ 53' �i� , �� .,,�• *y 1 tt � ,_.__. : t �% 3 f�.,�':; .r�,f � � ..__� � •_- f..-._..._.- t_.. �...a{` �r__... `, ! i \\ 'a7 i W1la ! 52 51 -- 7' ' ? ? t✓/` it C�RLLCM i?V47 i - , r--v:•---._..-. _ _ Ins `�Ai•i�f � r.• �,� ;''i i\ :;'��.r.-„ / S13 3� �,li� -�-,! 47� �'i �_ - `_.� �0� �I i S � ''. , lk iG l /��i f '. i (._.'? `,,—.' ! � � 3 i i i ! i F 1 d +-' j :,c� ? 1----ram 11 'J3 ! t..:: i• 1�} i1 `�`✓ i - t `� t', .�''i i U `!jt E i R (`,�`�t`(y�.J,yf i p G i C`, t jj( tt '7� ! !i t { S8 ,' .S bj tt'� j ' L7 if� (�6, •••-...lt t ....,-�...__...._ f j �.-.!—�..J : ... �-6 'ill . rE'' ^ 3 "'t'� ii7 , L%%r.:,2^I.._.-.-F�._.._.,_..�•---•.•� ; t ; = fii r : ua t '381 5 *4 S90 �"i— L'� "'! i.fv t JJU f f':j (i •.-.) I 1� ,I �••r ,lid IS9 2 (` I! 25 �� �: ? i' t� �! - ,7f} n i V3 i� : Lr,l I ?: j j!/ i r —' i .' i i f�_ i S y. `� 1 L/'3 ill t.L. 11 Ii�vi:iA3sf Jk�! i S t i I i q ,} �7 ,p r + q q q q , '.. .., t) (-' w e ff' L�' i �J 1 `t o r �'i' �3• i i `� S '�J a 1 _ �,..:.,,#r-.`_� i SCALE 1 -1000 //3/� i , __ __ ___ _ _� i z i o j 2� , ; , r C = r C !� >- t j { 1=a �"� �ry 2v t.�}! i { �V r � t'?l 1 yr � `' N IV •� �`�� "'�"-'`• �1 L�f 1 jt (.'t g4vJ f f I UIR.•L.U. AV Jail ,LLr i�ii � €� GC� �� � cat ``,•� `�'f � Ii �� �a`a�•s J�/ J `• 1'' f =1 + W7b 2W127 ! < f So 10 Cti _)3w A"; i{ F __ --- 13Q C Ss OLD BLACZ, s:. S1 ` t �r s 1 sill RfVER Cl�!>iN S16 p # �r 1.... i I ✓ ,.c f / r \ ��l - l J�' �t 1-\ END CD 2 FEk PIPE BM4CH Na 2 S17 t•tivt MAPH INPUT t.aca;rioft ' ' ,pj" , FOP HSPF SUBBASm S17 (SPRwBROGN) � �. # :tt v e D!Ahi��iEii 5TOR1, AfiA4P I ` —Er STi2EA9=4/�?iLVAL4Gr CfiAIVNc'i HYDROGWIi {NPV.L0C•AJlCit I l r p S17 e \`• ow,F€0 �r tUtND NO t P5 ,� 35 ff,��;;•,, '�; ,� 1 FEa a A.�+i N 4 FOR Hs�t susaas{n ps �p�trn+� ? � I S5 �� 33 �� ILL 72 �`' W C- `: `. - T=5 =4'� ` ``.^r am- cY CREEK ��� ��� �f1�''/J/f"• r 1�=� .....-l� ' \tip``:•`��;I� _-- _ _ �•{s _ __ _ TUlW AP•Ji"Ttl��MI�T--Sp 'E' OfCITY F0 Rarti : ����.�.����„�"R �� _ �..�..-_.-:-._� ♦ .z..-.�, \. �is1 �..._.-_ \ i HYDRAULIC ANALYSIS FOR FLOOD PLAIN p( y y\j� jffjf/Y�/ \\ ; �'.�. ; ,,.•y t ,r-'' - ='�-_" �{!;�••±—_,•t--�-9-__ MAPPING STUDY OF SPRINGBROOK CREEK CJt.F',Cf� `. \ ; � ~�` '_"�J i, ' � Jam\ S , ;`,/` Ir-" k 1 .._.-_ -' "f ri f -^,, •�`1 YE 7 E }YA:..L?y RIVER Y _ -� ��w �_✓•? i ,�, ---; FIGURE 2 "'� FEO MODEL SCHEMATIC STATION 3O GREEN-•CIUVYAkfS RIVER FEQ Model Development Table 2 presents the pump station operation with no restriction by high Green River flows. The pump station operation uses a defined series of pumps for each elevation that are added to obtain the overall pumping rate. Table 2 BRPS — Operation Unrestricted by Green River Flow Elevation at BRPS Pump Discharge Forebay (NVGD 1929) (ft) (cfs)l 0 0 0.37 0 2.28 0 2.38 70 2.53 70 2.63 205 2.77 205 2.88 340 3.78 340 3.88 960 4 960 4.03 960 4.13 1360 4.28 1360 4.38 1700 4.53 1700 4.63 1700 4.79 1700 4.89 1700 6 1700 8 1700 10 1700 13 1700 15 1700 18 1700 100 1700 BRPS Pumped Discharge (cfs) Pumps in Operation (See Table 1) 70 1S 205 1M+1S 304 2M+1S 960 2L (P3 & P6) 1360 3L 1700 3L +2M +1 S R:\Seattle\l I-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06R. W. Beck 2-5 Section 2 As noted above the pump station must restrict pumping rates when the Green River is high. The POPP specifies a maximum allowable discharge as a step function of flow on the Green River at Auburn. These maximum allowable discharges are, however, not related to the physical capabilities of the pumps installed at the BRPS. For the purpose of the modeling completed in 1996, an assumed pump operation that was more directly tied to the actual pumps and their capacities was used. The modeled operation of the BRPS is presented in Table 3 (excerpted from nhc, 1995). Essentially, the modeled operation rule constrains the number of pump units which may be operated for a given flow at Auburn based on the physical capacities of the installed pumps, rather than the current regulatory targets. The modeled operation rule assumes discharges less than those specified in the GRIA except when flows on the Green River exceed 11,000 cfs. The modeled discharge scenario was felt to be more realistically represent how the BRPS is operated (i.e., using one or two large pumps rather than a combination of multiple small pumps). It is noted that since the work completed in 1995, one of the larger pumps (P5) was made operational. The modeled operating rules developed in 1995 were not changed for this FEMA update. By not adding the large pump (480 cfs) to the modeling operating rules, a redundancy is build into the analysis should any of the large pumps fail during a significant event. Also noted is that the maximum flows in the system during the 100-year conveyance event, 1,307 cfs, is below the modeled capacity of 1,700 cfs and thus adding the pump would have a negligible affect on the results. Green River Discharge at Auburn Gage (cfs) Table 3 BRPS - Assumed Operation Rules Restricted by Green River Flow Maximum Number of Pumps in Operation Assumed Discharge Rate for Modeling (cfs) Maximum Allowable Discharge from the 1986 POPP Less than 9000 3L + 2M + 1 S 1700 2945 9000 to 9500 3L + 2M + 1 S 1700 2900 9500 to 10000 3L + 2M + 1 S 1700 2400 10000 to 10500 3L + 2M + 1 S 1700 1900 10500 to 11000 3L (P3, P6 & P8) 1360 1400 11000 to 11500 2L (P3 & P6) 960 900 11500 to 12000 1 L 480 400 More than 12000 0 See Note 3 400 to 0 L = large pump, nominal capacity 514 cfs M = medium pump, nominal capacity 150 cfs S = small pump, minimal capacity 75 cfs 1. Assumed discharge rates are based on pump performance curves, anticipated static head, and pump tests. See Table 1 for listing of discharge rate assumed for each pump. 2. The maximum number of pumps, and thus the assumed discharge rate, does not include 1 large pump (P5) made operational since 1995 to build in redundancy into the analysis. 3. A BRPS discharge of 0 cfs was assumed when the Green River discharges exceed 12,000 cfs to model the most conservative scenario for the "storage" event. 2-6 R. W. BeckRASeattle\11-00781 Springbrook Creek FEMA remapptng\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 FEQ Model Development During model simulations FEQ performs a two -rule check. For each time step, the model checks the elevation at the BRPS forebay (Table 2) to identify a discharge rate. For the same time step, the discharge on the Green River at Auburn is also checked (Table 3) to identify if pumping rates are constrained. FEQ then simulates the lesser of the two BRPS discharges for that time step. In addition to the downstream boundary condition, there are four upstream boundaries that represent the major stream inputs into the model. These include Springbrook, Mill, Rolling Hills and Panther creeks. The model extends beyond the study reach (just south of SW 43rd Street) so that separate hydrographs could be used for Springbrook Creek and Mill Creek. A short section of Rolling Hills Creek is included upstream of the study reach that includes a parallel culverts under I-405. Also, a short section of Panther Creek is included that extends upstream of the SR 167 crossing. 2.3 Inflow Hydrographs In addition to the inflow hydrographs for Springbrook, Mill, Rolling Hills and Panther creeks discussed in the previous section, there are also hydrographs inputs for other subbasins within the valley area. These subbasins are shown on Figure 1 and the location where the hydrograph inputs are entered into the model are shown on Figure 2. Table 4 included a listing of the hydrograph input numbers that reference the hydrograph numbers used in the HASC. Table 4 Input Hydrograph Identification HASC FEQ Identification Identification Number Number Springbrook Creek S1 43 S2 37 S3 35 S4 33 S5 31 S6 29 S7a 27 S7b 23b S8 25 S9a 15 S9b 21 S9c 23a S10 17 RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06R. W. Beck 2-7 Section 2 HASC FEQ Identification Identification Number Number S11 19 S12 13 S13 11 S14 7 S15 9 S16a 2 S16b 3 S16c 4 S17 5 S18 1 US120 39 US130 41 Panther Creek P1 109 P2 107A P3 107B P4 101 P5 103 2.4 Simulation Scenarios Due to the two possible operation scenarios at the BRPS, two different simulation scenarios were developed for the 50 and 100-year events. One of the scenarios, referred to as the conveyance scenario, reflects a severe local event without BRPS pumping restrictions. This simulation assesses the conveyance capacity of Springbrook Creek. The other scenario, referred to as the storage scenario, reflects a severe Green River flood that causes the pump station to restrict its pumping rate. The storage scenario assesses the BRPS forebay's as well as Springbrook Creek's and its associated wetlands' ability to temporarily contain the flood waters when the pump station discharge capacity is restricted. The higher of the resulting water levels for the two scenarios was used to determine the flood profile for the various frequency events. Only the conveyance scenario was used for the 10-year event. The storage scenario was not a concern because it was determined via frequency analyses of peak annual storage volumes in the BRPS forebay (NHC, 1996) that this event would create only a negligible build-up of storage in the forebay during high Green River flows. 2-8 R. W. BeckR:\Seattle\l1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doe 8/9/06 FEQ Model Development 2.5 Cross Section Validation As noted above, the hydraulic model was originally developed in 1996. Cross section data in the model came from a variety of sources including field survey by NRCS (formerly SCS) in 1990, more recent survey by W&H Pacific and R.W. Beck, channel design drawings, and 1980 COE topography. It is understood that many of the data sources (i.e., cross -sections) were not "as -built". In order to confirm that cross sections used in the model generally agree with the existing channel conditions, a validation or comparison was performed. Six channel cross sections were surveyed and compared to the cross sections used in the FEQ model in order to confirm use of the cross sections in the model is reasonable. Details of the cross section validation are included in Appendix B. The six cross sections that were selected for validation are located along reaches where the modeled cross section was based upon prior design drawings and older surveyed reaches. These include; ■ Three sections downstream of SW 16th Street where the cross sections were based upon SCS construction drawings or survey by SCS done in 1990 ■ One section along the reach between SW 16th Street and the new Oakesdale Avenue Bridge, where the cross sections were based on design drawings for the channel widening in this area but no as-builts are available ■ Two upstream of SW 41st Street, where cross sections were based on channel widening design drawings which were part of the Oakesdale Business Park development Please refer to the map in Appendix B for the location of the cross sections selected for the validation. It was recognized that some differences between the modeled cross section and new surveyed cross sections would be likely. However, upon comparing the newly surveyed cross sections and the cross sections used in the 1996 model, the extent of the differences, particularly downstream of SW 16th Street is fairly significant. Due to the differences in the surveyed and modeled cross section downstream of SW 16th Street, a sensitivity analysis was performed using an existing HEC-RAS model of the area which uses the same cross sections as the FEQ model. The sensitivity analysis was performed to see if the differences in the cross sections had a significant effect on the water surface profiles. The results of the sensitivity analysis showed that using the new surveyed cross sections increased water surface elevations by more than one foot in some locations. The higher elevation continued upstream, although the increase in elevation decreases as you move upstream. This difference in simulated water levels is greater than the desirable accuracy of the modeling and therefore a new survey was conducted in between the upstream end of the forebay to SW 16th Street and the newly surveyed cross sections (included in Appendix B) were used to modify the FEQ model for this floodplain mapping study. RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydmulicsFinaLdoc 8/9/06R. W. Beck 2-9 Section 2 2.6 Function Tables for FEQ Model Function tables are used to describe the various features such as channel and floodplain geometry, bridges, culverts, level pool reservoirs, inflow hydrographs and the operation of the BRPS. The function tables for the operation of the BRPS were described in Section 3.2. Table 5 describes the channel and floodplain geometry function tables, invert elevations, their data sources, and roughness (Manning's) coefficients. Table 6 describes the bridge and culvert function tables, inverts and overtopping elevations, and roughness coefficients and their data sources. In addition, Appendix C includes a summary table of FEQUTL files used in this analysis. The Springbrook Creek valley wetlands are shown in Figure 1. Several of the wetlands were modeled as part of the Springbrook Creek channel including wetlands 3, 4, 6, 7a and 7b, and the BRPS forebay (PSFBY). The City .has removed the berm between wetlands 7a and 7b such that they are now both contiguous with the creek. The remaining wetlands were modeled as level pool reservoirs because they are separated from the creek, but are connected via a pipe system or by overbank flow conditions during high flows. These include wetlands 12, 5, 7c, 11 a, 11 b and 11. Wetlands 11 a, I I and 11 make up the Panther Creek Wetland. The data sources for the wetlands that were modeled as part of channel cross sections are listed in Table 5. The storage data (stage -area relationship) for the wetlands modeled as level pool reservoirs was based on 1980 Corps of Engineers topographic mapping. Wetland 11 a, 11 b, and 11 are distinct cells. Wetland 11 and 11 b are separated by a low berm that serves as a utility access road. This berm is overtopped during high flows and the wetland cells become connected. Wetland 1 lb and 1 la are separated by a tall berm that is not overtopped. A small diameter culvert connects these two wetland cells. Wetland 12, shown schematically on Figure 1, actually consists of a series of smaller ponds. Exhibit B shows the actually extents of these ponds. There are four pond cells connected by culverts that drain to Springbrook Creek south of SW 16th Street. There is also a crescent shaped wetland that drains to Springbrook Creek between SW 19d' Street and SW 23rd Street. In an effort to simplify the FEQ model during the 1996 analysis the ponds as well as the crescent shaped wetland areas within the S 11 subbasin were assumed to be combined in the model to form a single level pool reservoir to reflect the cumulative storage of the ponds. Stage storage data for the representative pond was based on the Boeing Customer Service Training Center (CSTC) information (Sverdrup, 1992). The combined wetland 12 level pool reservoir was also assumed to connect to Springbrook Creek at one location (See Figure 2) between branches 10 and 13. In reality, the major portion of the wetland is connected at this location; however the smaller crescent -shaped pond to the south has a separate connection between branches 14 and 16. It is noted that while the crescent -shaped pond to the south is connected to Springbrook Creek by a culvert with no flap gate, the connection for the north series of ponds has a flap gate. Therefore, the modeled connection included both pipes, one with a flap gate and the other without. 2-10 R. W. BeckRASeattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9106 FEQ Model Development The inflow hydrographs were extracted from the hydrology developed by NHC for this project. Tables B2 and B3 of the HASC shows the events and multipliers that were used to reflect the various flood events. R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9i06R. W. Beck 2-1 1 Section 2 2-12 R. W. BeckR:\Seattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) Table 5 Cross Section and Floodplain Data' FEQ Model Development BRANCH NODE ID X- SECTION NO. LOCATION IDENTIFIER STATION (FT) STATION (MILES) INVERT ELEVATION (NAVD 1988) CHANNEL DATA SOURCE OVER BANK DATA SOURCE LHS Roughness Coefficients FEQ input file Center RHS IFEQUTL Input file SPRINGBROOK CREEK 72 PSFORBYD 2050 Black River 0 0.000 -4.92 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat Pump Station "As -built" "As -built" construction construction drawings drawings PSFORB10 2051 170 0.032 -1.17 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY9 2052 225 0.043 -0,22 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY8 2053 505 0.096 3.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY7 2054 635 0.120 3.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-13 Section 2 Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file PSFORBY6 2055 825 0.156 1.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spdng2.dat 'As -built" "As -built" construction construction drawings drawings PSFORBY5 2056 1035 0.196 1.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY4 2057 1305 0.247 3.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY3 2058 1640 0.311 1.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY2 2059 1715 0.325 1.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings PSFORBY1 2060 1835 0.348 1.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings 2-14 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 f_, Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X. INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file PSFORBYU 2061 1950 0.369 3.58 SCS forebay SCS forebay 0.1 0.03 0.1 Xtabs.spg/Spring2.dat "As -built" "As -built" construction construction drawings drawings 1 SBRKAD 4010 2000 0.379 2.97 RW Beck City of 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Renton Base Mapping (1999) SBRKAU 4012 2220 0.420 2.84 RW Beck City of 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Renton Base Mapping (1999) 4 SBRKBD 4012 2220 0.420 2.84 RW Beck City of 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey 2003 Renton Base Mapping (1999) SBRKB1 4014 2537 0.480 3.76 RW Beck City of 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey 2003 Renton Base Mapping (1999) SBRKBU 4015 2840 0.538 4.89 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey 2003 Survey 2003 5 SBRKCD 4015 2840 0.538 4,89 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Survey 2003 SBRKC4 4016 3266 0.619 5.05 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Survey 2003 RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-1 5 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL input file SBRKC3 4018 3754 0.711 4.74 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Survey 2003 SBRKC2 4019 4280 0.811 3.27 RW Beck City of 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Renton Base Mapping (1999) SBRKC1 4020 4669 0.884 4.36 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 Survey, 2003 Survey 2003 SBRKCU 2074 Grady Way 4728 0.895 4.58 SCS forebay 0.1 0.045 0.1 Xtabs.spg/Spring2.dat d/s "As -built" construction drawings 6 SBRKDD 4028 Grady Way 4961 0.940 3.58 RW Beck RW Beck 0.1 0.045 0.1 xtabs.703/xtabin.703 u/s Survey, 2003 Survey, 2003 SBRKD1 4021 5077 0.962 4.58 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 SBRKDU 4022 5476 1.037 3.07 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 7 SBRKED 4022 5476 1.037 3.07 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 SBRKEU 4025 5560 1.053 4.97 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 2-16 R. W. Beck RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file 9 SBRKFD 4027 5564 1.054 4.97 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 SBRKFU 4027 16th d/s 5620 1.064 4.97 RW Beck RW Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 10 SBRKGD 9004 16th u/s 5682 1.076 5.08 Oakesdale Oakesdale 0.1 0.045 0.1 xtabs.703/xtabin.703 Avenue SW Avenue SW Extension Extension Phase 1 Phase 1 Record Record Drawings Drawings (December (December 1997) 1997) SBRKG3 9004 5777 1.094 5.08 Oakesdale Oakesdale 0.1 0.045 0.1 xtabs.y2k/xtabin.y2k Avenue SW Avenue SW Extension Extension Phase 1 Phase 1 Record Record Drawings Drawings (December (December 1997) 1997) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-1 % Section 2 Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRKG2 9005 5850 1.108 5.08 Oakesdale Oakesdale 0.1 0.045 0.1 xtabs.y2k/xtabin.y2k Avenue SW Avenue SW Extension Extension Phase 1 Phase 1 Record Record Drawings Drawings (December (December 1997) 1997) OAKBRD 9010 Oakesdale Br 5939 1.125 3.35 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt d/s Survey Survey (1999) (1999) OAKBRU 9012 Oakesdale Br 6039 1.144 2.77 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2,txt u/s Survey Survey (1999) (1999) SBRKGI 9014 6139 1.163 1.00 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKGU 9021 6489 1.229 3.34 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 13 SBRKHD 9021 6489 1.229 3.34 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKH2 9029 6889 1.305 3.40 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 2-1 8 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doe 8/9/06 FEQ Model Development Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRKH3 9030 6939 1.314 4.67 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2,ex/xtabine2.txt Survey Survey (1999) (1999) SBRKH4 9031 6989 1.324 4.40 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKH5 9032 7039 1.333 3.42 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKH6 9033 7089 1.343 1.50 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKHU 9035 7189 1.362 3.62 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 14 SBRKID 9035 7189 1.362 3.62 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKII 9036 7239 1.371 4.99 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKI2 9039 7389 1.399 4.88 WH Pacific WH Pacific 0.1 0.045 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKI3 9040 7439 1.409 3.29 WH Pacific WH Pacific 0.1 0.06 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-19 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file HDBRID 9043 Hunter 7589 1.437 3.46 Springbrook Springbrook 0.1 0.06 0.1 xtabs2.ex/xtabine2.txt Douglas Creek Bridge Creek Bridge Bridge Hunter Hunter Douglas Inc. Douglas Inc. "As-builts" "As-builts" (December (December 1997) 1997) SBRKI4 9052 8039 1.523 0.85 WH Pacific WH Pacific 0.1 0.06 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKI5 9053 8089 1.532 1.83 WH Pacific WH Pacific 0.1 0.06 0.1 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKIU 9055 8189 1.551 1.34 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 16 SBRKJD 9055 8189 1.551 1.34 SBRKJ1 9056 8239 1.560 1.55 SBRKJ2 9058 8339 1.579 1.84 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 2-20 R. W. Beck R:\Seattle\l1-00781 Springbrook Creek FENLA. remapping\Reports\FENIA Final\SpringbroolcHydraulicsFinal.doc 8/9/06 FEQ Model Development Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file SBRKJ3 9065 8689 1.646 4.35 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKJ4 9069 8889 1.684 3.90 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKJ5 9071 8989 1.702 4.03 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKJU 9073 9089 1.721 4.11 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 17 SBRKKD 9073 9089 1.721 4.11 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKK1 9075 9189 1.740 4.42 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKKU 9078 9491 1.798 6.00 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 18 SBRKLD 9078 9491 1.798 6.00 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-21 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file SBRKMU 9079 private bridge 9691 1.835 5.40 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt d/s Survey Survey (1999) (1999) 19 SBRKMD 9082 private bridge 9766 1.850 5.40 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt u/s Survey Survey (1999) (1999) SBRKM1 9080 10092 1.911 5.70 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) SBRKMU 9081 27th Ave d/s 10213 1.934 5.40 WH Pacific WH Pacific 0.7 0.04 0.7 xtabs2.ex/xtabine2.txt Survey Survey (1999) (1999) 20 SBRKND 9102 27th Ave u/s 10309 1.952 6.54 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) SBRKNU 9102 10366 1.963 6.54 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 21 SBRKOD 9102 10366 1.963 6.54 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 2-22 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRK02 9103 10435 1.976 6.72 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) SBRK01 9104 10937 2.071 5.57 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) SBRKOU 9105 11344 2.148 5.38 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 23 SBRKPD 9105 11344 2.148 5.38 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) SBRKPU 9106 11882 2.250 6.55 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 24 SBRKQD 9106 11882 2,250 6.55 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-23 Section 2 Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRKQU 9107 12370 2.343 6.92 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 25 SBRKRD 9107 12370 2.343 6.92 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) SW34TH 9107 34th d/s 12502 2.368 6.92 R.W. Beck City of 0.7 0.04 0.7 xtabs2.301/xtabin2.301 Survey, 2001 Renton Base Mapping (1999) 26 SW34TH 9108 34th u/s 12661 2.398 7.44 R.W. Beck R.W, Beck 0.7 0.04 0.7 xtabs2.3011xtabin2.301 Survey, 2001 Survey, 2001 SBRKSI 9109 13061 2.474 6.40 R.W. Beck R.W. Beck 0.7 0.04 0.7 xtabs2.3011xtabin2.301 Survey, 2001 Survey, 2001 SBRKSU 9110 13661 2.587 6.89 R.W. Beck R.W. Beck 0.07 0.04 0.07 xtabs2.301/xtabin2.301 Survey, 2001 Survey, 2001 27 SBRKTD 9110 13661 2.587 6.89 R.W. Beck R.W. Beck 0.07 0.04 0.07 xtabs2.3011xtabin2.301 Survey, 2001 Survey, 2001 SBRKTI 9111 14061 2.663 8.43 R.W. Beck R.W. Beck 0.07 0.04 0.07 xtabs2.301Ixtabin2.301 Survey, 2001 Survey, 2001 2-24 R. W. Beck R:\Seattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRKTU 9112 RR bridge d/s 14637 2.772 8.52 R.W. Beck R.W. Beck 0.07 0.04 0.07 xtabs2.301/xtabin2.301 Survey, 2001 Survey, 2001 30 SBRKTD SW41ST 9115 9114 RR bridge u/s 14710 41std/s 14970 2.786 2.835 7.15 7.47 R.W. Beck Survey, 2001 R.W. Beck Survey, 2001 R.W. Beck Survey, 2001 R.W. Beck Survey, 2001 0.05 0.05 0.04 0.04 0.05 0.05 xtabs2.301/xtabin2.301 xtabs2.301/xtabin2.301 31 SW41ST 2076 41stu/s 15235 2.885 10.10 Oakesdale City of 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Renton Base Campus Mapping Phase 2 "As- (1999) builts" (November, 1999) SBRKVI 2077 15335 2.904 10.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-25 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file SBRKV2 2078 15435 2.923 9.50 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKV4 2080 15535 2.942 10.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKV5 2081 15735 2.980 10.40 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKV6 2082 15835 2.999 9.90 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) 2-26 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file SBRKV7 2083 15935 3.018 10.30 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKVU 2085 16135 3.056 11.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts' (November, (November, 1999) 1999) 33 SBRKWD 2085 16135 3.056 11.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 'As- builts" builts" (November, (November, 1999) 1999) SBRKW1 2086 16235 3.075 12.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-27 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS /FEQUTL Input file SBRKW2 2087 16335 3.094 10.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKW3 2088 16435 3.113 10.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabiQ.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKW4 2089 16535 3.132 10.30 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKW5 2090 16635 3.151 11.10 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) 2-28 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Table 5 (cont.) FEQ Model Development Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file SBRKW6 2091 16735 3.170 11.10 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SBRKW7 2092 16835 3.188 11.90 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SW43RD 2093 43rd d/s 16935 3.207 10.00 Oakesdale Oakesdale 0.07 0.04 0.07 xtabs2.oak/xtabin2.oak Business Business Campus Campus Phase 2 "As- Phase 2 "As- builts" builts" (November, (November, 1999) 1999) SW 23rd STREET DRAINAGE CHANNEL 450 P9CHABAD 8040 9.18 City of City of Renton HEC- Renton 2 model, HEC-2 1995 model, 1995 0.09 0.05 0.05 p9.a2a/p92.hc2 RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-29 Section 2 Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file P9CHANA3 8041 420 0.080 8.58 City of City of 0.09 0.05 0.05 p9.a2a/p92.hc2 Renton HEC- Renton 2 model, HEC-2 1995 model, 1995 P9CHANA2 8042 500 0.095 8.58 City of City of 0.09 0.05 0.05 p9.a2a/p92.hc2 Renton HEC- Renton 2 model, HEC-2 1995 model, 1995 P9CHANA1 8043 550 0.104 8.58 City of City of 0.09 0.05 0.05 p9.a2a/p92.hc2 Renton HEC- Renton 2 model, HEC-2 1995 model, 1995 P9CHANAU 8044 810 0.153 8.58 City of City of 0.09 0.05 0.05 p9.a2a/p92.hc2 Renton HEC- Renton 2 model, HEC-2 1995 model, 1995 45 P9CHAND 8050 896 0.170 6.58 City of City of 0.09 0.05 0.09 xtabs2.ex/xtabine2.txt Renton HEC- Renton Base 2 model, Mapping 1995 (1999) P9CHANU 8050 947 0.179 7.28 City of City of 0.09 0.05 0.09 xtabs2.ex/xtabine2.txt Renton HEC- Renton Base 2 model, Mapping 1995 (1999) 2-3 Q R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 FEQ Model Development Table 5 (cont.) Roughness Coefficients OVER X• INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file 461 P9CHANBU 8045 1061 0.000 7.49 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) P9CHANBD 8045 1066 0.001 7.49 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) 46 P9CHANBD 8045 1066 0.202 10.68 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) P9CHANBU 8046 1110 0.210 7.68 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) 47 P9CHANCD 8046 1110 0.210 7.68 City of City of 0.09 0.05 0.09 p9.a2a/p92,hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) P9CHANC2 8047 1545 0.293 10.48 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doe 8/9/06 R. W. Beck 2-3 1 Section 2 Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file P9CHANC1 8048 2075 0.393 11.58 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) P9CHANCU 8049 2292 0.434 12.58 City of City of 0.09 0.05 0.09 p9.a2a/p92.hc2 Renton HEC- Renton Base 2 model, Mapping 1995 (1999) 81 P9CHAN 9009 2391 0 10.48 Panther City of 0.09 0.04 0.09 xtabs.y2k/xtabin.y2k Creek, Renton Base SR167 Mapping Culvert (1999) Drawings, 2000 9013 2492 0.019 9.68 Panther City of 0.09 0.04 0.09 xtabs.y2k/xtabin.y2k Creek, Renton Base SR167 Mapping Culvert (1999) Drawings, 2000 80 P9CHAN 9008 0 0 11.58 Panther Panther 0.09 0.04 0.09 xtabs.y2k/xtabin.y2k Creek, Creek, SR167 SR167 Culvert Culvert Drawings, Drawings, 2000 2000 2-32 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 FEQ Model Development Table 5 (cont.) Roughness Coefficients OVER X- INVERT CHANNEL BANK SECTION LOCATION STATION STATION ELEVATION DATA DATA FEQ input file BRANCH NODE ID NO. IDENTIFIER (FT) (MILES) (NAVD 1988) SOURCE SOURCE LHS Center RHS IFEQUTL Input file 9008 11 0.002 10.22 Panther Panther 0.09 0.04 0.09 xtabs,y2k/xtabin.y2k Creek, Creek, SR167 SR167 Culvert Culvert Drawings, Drawings, 2000 2000 BYPASS CHANNEL UNDER 1-405 64 BY405BD 4028 0 0.000 3.58 R.W. Beck R.W. Beck 0.1 0.045 0.1 xtabs,703/xtabin.703 Survey, 2003 Survey, 2003 BY405BU 4029 139 0.026 4.94 R.W. Beck R.W. Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 63 BY405AD 4029 139 0.026 4.94 R.W. Beck R.W. Beck 0.12 0.05 0.12 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 BY405AU 4026 589 0.112 6.28 R.W. Beck RW. Beck 0.12 0.05 0.05 xtabs.703/xtabin.703 Survey, 2003 Survey, 2003 ' Elevations in NAVD 1988. To convert to NGVD 1929, subtract 3.58. R:\Seattle\l 1-00781 Springbrook•Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 R. W. Beck 2-33 Section 2 Table 6 Hydraulic Structure Data' Hydraulic Structure2 Description Data Source Invert Elevation Low Chord Elevation Top of road Elevation Roughness Coefficients FEQ input file/ FEQUTL input file Grady Way Box Culverts Three 11'xl0.3' and one 1986 Grady Way Construction 3.81 17.81 26.76 0.012 GradyB.tab/Grady.byp 11'xl4' Box Culvert Drawing 1-405 box culvert Four-11'xl 1', one-11'x13' Box Culvert P-1 Design Drawings 3.68 16.68 28 0.012 Byp.Tab SW 16th Street Brigde Bridge SW 16th Street Bridge 3.82 19.58 22.58 0.05 to 0.12 twodtabs.1 6/twodin. 16 Replacement As -built Private Bridge north of SW Bridge NRCS survey 1990 6.78 17.78 19.81 0.04 to 0.07 twodtabs.alVtwodin.alt 27th Street SW 27th Street Box Culvert 30' x 10' Box Culvert SW 27th Street Culvert 7.08 16.83 20.9 0.023 twodtabs.lst/twodin.lst Repaacment Project As -built SW 34th Street culverts Four 6' diameter cmps NRCS survey 1990 8.58 14.58 18.38 0.024 twodtabs.alVtwodin.alt Railroad Bridge Bridge R.W. Beck Survey, 2001 7.18 18.64 19.7 0.035 twodtabs.rr/twodin.rr SW 41 st Street culverts Four 6' diameter cmps NRCS survey 1990 10.58 16.58 20.68 0.021 twodtabs.alt/twodin.alt Oakesdale Business Park 9'x34' Box Culvert Oakesdale Business Campus 10.58 19 20.68 0.025 twodtabs.oak/twodin.oak Access Road Box Culvert Phase 2 "As-builts" (November, 1999) Olympic Pipeline Culvert 10'x4' Box Culvert Olympic Pipeline Culvert 4.6 8.5 14.9 0.021 twodtabs.IsUtwodin.lst Replacement As -built Lind Avenue Culverts Two 14'x9' Culverts NRCS survey 1990 7.49 16.49 23.08 0.03 twodtabs.alUtwodin.alt East Valley Road Culvert Two 4' diamter culverts SR-167 84th Avenue S to S 9.68 13.68 19 0.024 twodtabs.IsUtwodin.lst Grady Way Culvert Construction Drawings SR 167 Culvert One 6' diameter culvert SR-167 84th Avenue S to S 10.48 16.48 28 0.012 twodtabs.IsUtwodin.lst Grady Way Culvert Construction Drawings I Elevations in NAVD 1988. To convert to NGVD 1929, subtract 3.58. 2 The two Oakesdale Avenue SW bridges, the SW 7th Street Bridge, the 1-405 bridge and the Hunter Douglas access bridge were not included in the model because they are elevated above the floodplain 2-34 R. W. Beck R:\Seattle\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 FEQ Model Development 2.7 FEQ Model Validation In general there is limited information available with which a detailed model calibration or validation could be conducted. Several large storms have occurred in the system since the previous FEMA study (such as in 1990 and 1996), however, because conveyance improvements were completed after these events, the system no longer resembles the system that existing at that time. The best hydraulic information available for a large storm event with the current Springbrook Creek system is for the November 14, 2001 event. This storm had a return period between 2 and 10 years. Before conducting the validation, a one -day field reconnaissance was performed to observe channel conditions and vegetation along the channel banks. Prior roughness coefficients (developed for the 1996 study) were be reviewed and updated to reflect current channel conditions. The results of the field reconnaissance are contained in Appendix B. Once the roughness coefficients were adjusted to reflect existing conditions, the model was used to simulate the November 14, 2001 storm. The resulting simulated water surface elevations were compared to observed November 14, 2001 high water levels where available. The results of this comparison are shown in Table 7. Note that the resulting water level at the railroad bridge downstream of SW 41 sl Street was initially not within the desired tolerance (+/- 0.5 feet). Based on these results, the roughness coefficients in the vicinity of the railroad bridge were reviewed and it was noted that roughness coefficients originally assigned to the channel and overbanks from approximately the confluence with the SW 23`d Street drainage channel to SW 43`d Street appeared to be slightly low. The roughness coefficients for the overbanks were increased from 0.05 to 0.07 and the channel coefficients were changed from 0.03 to 0.04 through this area. With this modification, the resulting water surface elevations were within 0.5 feet of the measured elevations and the validation was deemed acceptable. R:\Seattle\l1-00781 Springbrook Creek FEMA remapping\Reports\FEMA FinallSpringbrookHydraulicsFinaLdoc8/9/06R. W. Beck 2-35 Section 2 Table 7 FEQ Validation using the November 2001 Storm Event' Simulated Survyed Simulated High Water High Water High Water Elevation — Updated Elevation Elevation Difference updated Difference Location (Feet) (Feet) (Feet) (Feet)2 (Feet) Springbrook Creek Upstream side of Oakesdale/ SW 41st Street culvert crossing 19.08 18.77 0.30 19.16 -0.08 Springbrook Creek Railroad Crossing downstream of SW 41 st Street 17.98 17.25 0.73 17.63 0.36 East Valley Road and SW 23rd Street Drainage Channel 16.92 17.11 -0.19 17.01 -0.09 Springbrook Creek Old Bridge north of SW 27th Street culvert 15.34 15.14 0.20 15.21 0.14 1 Elevations in NAVD 1988. To convert to NGVD 1929, subtract 3.58. 20verbank roughness coefficents adjusted from approximately 1350 feet downstream of the railroad bridge to SW 431d Street. 2.8 Volume Comparison A volume comparison was performed to check for consistency between the HSPF model and the FEQ model. The runoff volume comparison was done for the "conveyance and the "storage" events. In both cases the runoff volume compared well between the two models with FEQ having a slightly higher volume (1.1 percent and 2.4 percent for the conveyance and storage events, respectively). One of the potential reasons for FEQ having a slightly higher volume is that all input hydrographs that are entering the system through branches, such as pipes, must have a non -zero value (i.e., pipes can't run dry or simulations stop). The minimum flow in the branches may add slightly to the overall volume. Overall, the comparison provides a good check for consistency and provides verification that all HSPF generated runoff volume is accounted for the hydraulic analysis. A memorandum describing the comparison can be found in Appendix D. 2-36 R. W. BeckRASeattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Section 3 FLOOD PROFILES The water surface elevation results of the FEQ model simulation for the 10-, 50- and 100-year events are presented in Table 8 and plotted in Exhibit A. The elevation reference for the results is NAVD 1988. Table 9 presents peak flow results at several locations throughout the system. The complete output it included in. the digital appendix in Appendix C. The resulting base flood water surface elevations are considerably lower, especially at the downstream end of the study reach, than in the previous FEMA study of Springbrook Creek. At the upstream end of the study reach, the base flood water surface elevations are about the same. The difference between the base flood water surface elevations is a result of several factors: ■ Conveyance Improvements. Several conveyance improvements constructed since the last FEMA study have reduced several hydraulic restrictions and help to lower water surface elevations. ■ Capacity at the Black River Pump Station. The capacity of the BRPS at the time of the prior hydrologic and hydraulic study was 875 cfs. The current capacity is approximately 2180 cfs when all the operational pumps are included, although the simulated maximum capacity of 1700 cfs was used in the FEQ modeling to build in some pump redundancy. ■ Unsteady Flow Analysis. The previous FEMA study used a steady state model to evaluate the flood profiles along Springbrook Creek. With a steady state model, flows are input as a constant, and the model does not allow for attenuation of the peak as a storm is routed through the system. For a basin such as Springbrook Creek, which contains a considerable amount of storage, the attenuation can be significant. By accounting for the flow attenuation, the unsteady model resulted in lower flows in the downstream end of the study reach, and therefore, the corresponding base flood water surface elevations are lower in this area. ■ Updated Channel Cross Section Data and Topographic Mapping. The current FEMA study incorporates new topographic mapping data used to provide information on the floodplain as well as new field survey of channel cross sections. RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Section 3 Table 9 Simulated Peak Flows at Selected Locations 10-, 50-, and 100-Year Floods Location/Description FEQ Node ID 10-Yr Flow Conveyance Flow (cfs) 50-Yr Flow Conveyance Flow (cfs) 50-Yr Flow Storage Flow (cfs) 100-Yr Flow Conveyance Flow (cfs) 100-Yr Flow Storage Flow (cfs) SW 23rd Street Channel d/s of East Valley Road 4701 130 189 99 197 156 Springbrook Creek BRPS forebay outflow 7223 932 1128 1360 1195 1700 BRPS forebay inflow 7201 931 1126 851 1197 1309 Grady Way u/s 611+6402 825 1020 760 1085 1121 SW 16th Street 1015 821 1016 743 1081 1111 Confluence of Rolling Hills Creek 1301 811 1008 716 1073 1052 Confluence of SW 23rd St Channel 1601 769 955 663 1013 964 SW 27th d/s 1901 657 860 579 896 802 SW 27th u/s 2003 657 860 579 896 802 SW 34th d/s 2501 676 1029 580 1104 763 SW 34th u/s 2605 676 1029 580 1104 763 Oakesdale d/s 3001 684 1031 583 1112 770 Oakesdale u/s 3143 651 979 559 1061 744 SW 43rd d/s 3301 644 974 558 1053 747 3-2 R. W. BeckRASeattle\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal-doc 8/9/06 Section 3 Table 8 Simulated Water Surface Elevations 10-, 50-, and 100-year Floods 10-Percent-Annual- Chance Flood Water - Surface Elevation (feet) 2-Percent-Annual-Chance Flood Water -Surface Elevation feet 1-Percent-Annual-Chance Flood Water -Surface Elevation feet NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA CROSS- Storage Conveyance Storage Conveyance Water Surface Storage Conveyance Storage Conveyance Water Surface CROSS- SECTION NVGD NAVD SECTION BRANCH NODE ID NO. 1929 1988 Scenario Scenario Scenario Scenario Profile' I Scenario Scenario Scenario Scenario Profile' 0rM1rvVtlKVVn tlKrrn A 72 PSFORBYD 2050 3.88 7.46 10.75 4.07 14.33 7.65 14.33 13.11 4.09 16.69 7.67 16.69 PSFORB10 2051 3.87 7.45 10.75 4.07 14.33 7.65 14.33 13.11 4.09 16.69 7.67 16.69 B PSFORBY9 2052 3.87 7.45 10.75 4.07 14.33 7.65 14.33 13.11 4.09 16.69 7.67 16.69 C PSFORBYB 2053 3.86 7.44 10.75 4.06 14.33 7.64 14.33 13.11 4.07 16.69 7.65 16.69 D PSFORBY7 2054 3.91 7.49 10.75 4.09 14.33 7.67 14.33 13.11 4.11 16.69 7.69 16.69 PSFORBY6 2055 4.03 7.61 10.75 4.24 14.33 7.82 14.33 13.11 4.27 16.69 7.85 16.69 E PSFORBY5 2056 4.06 7.64 10.75 4.27 14.33 7.85 14.33 13.11 4.31 16.69 7.89 16.69 F PSFORBY4 2057 4.07 7.65 10.75 4.28 14.33 7.86 14.33 13.11 4.31 16.69 7.89 16.69 G PSFORBY3 2058 4.21 7.79 10.75 4.44 14.33 8.02 14.33 13.11 4A9 16.69 8.07 16.69 PSFORBY2 2059 4.22 7.80 10.75 4.46 14.33 8.04 14.33 13.11 4.51 16.69 8.09 16.69 PSFORBYI 2060 4.21 7.79 10.75 4.45 14.33 8.03 14.33 13.11 4.50 16.69 8.08 16.69 PSFORBYU 2061 4.20 7.78 10.75 4.44 14.33 8.02 14.33 13.11 4.48 16.69 8.06 16.69 H 1 SBRKAD 4010 4.26 7.84 10.75 4.55 14.33 8.13 14.33 13.11 4.63 16.69 8.21 16.69 1 SBRKAU 4012 6.02 9.60 10.76 6.41 14.34 9.99 14.34 13.11 6.54 16.69 10.12 16.69 1 4 SBRKBD 4012 6.19 9.77 10.76 6.65 14.34 10.23 14.34 13.11 6.76 16.69 10.34 16.69 J SBRKBI 4014 6.76 10.34 10.78 7.25 14.36 10.83 14.36 13.11 7.41 16.69 10.99 16.69 K SBRKBU 4015 7.28 10.86 10.80 7.82 14.38 11.40 14.38 13.11 7.99 16.69 11.57 16.69 K 5 SBRKCD 4015 7.28 10.86 10.80 7.82 14.38 11.40 14.38 13.11 7.99 16.69 11.57 16.69 L SBRKC4 4016 7.56 11.14 10.81 8.12 14.39 11.70 14.39 13.11 8.30 16.69 11.88 16.69 M SBRKC3 4018 7.84 11.42 10.83 8.42 14.41 12.00 14.41 13.11 8.61 16.69 12.19 16.69 N SBRKC2 4019 8.12 11.70 10.85 8.73 14.43 12.31 14.43 13.11 8.92 16.69 12.50 16.69 0 SBRKCI 4020 8.32 11.90 10.86 8.94 14.44 12.52 14.44 13.11 9.13 16.69 12.71 16.69 P SBRKCU 2074 8.41 11.99 10.87 9.04 14.45 12.62 14.45 13.11 9.23 16.69 12.81 16.69 Q 6 SBRKDD 4028 8.46 12.04 10.89 9.09 14.47 12.67 14.47 13.12 9.29 16.70 12.87 16.70 R SBRKDI 4021 8.44 12.02 10.89 9.07 14.47 12.65 14.47 13.12 9.27 16.70 12.85 16.70 T SBRKDU 4022 8.91 12.49 10.94 9.56 14.52 13.14 14.52 13.12 9.77 16.70 13.35 16.70 T 7 SBRKED 4022 8.91 12.49 10.94 9.56 14.52 13.14 14.52 13.12 9.77 16.70 13.35 16.70 U SBRKEU 4025 9.20 12.78 10.98 9.87 14.56 13.45 14.56 13.13 10.08 16.71 13.66 16.71 3-2 R. W. Beck R:\Suale" I-00781 Springbrook Cmek FEMA mmappingUt Nm\FEMA Fi.RSpringb-1LHyd.,d-Fi.1.d. 8/9I06 FLOOD PROFILES Table 8 (cont.) 10-Percent-Annual- Chance Flood Water - Surface Elevation (feet) 2-Percent-Annual-Chance Flood Water -Surface Elevation feet 1-Percent-Annual-Chance Flood Water -Surface Elevation feet NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA CROSS- Storage Conveyance 1 Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' Storage Conveyance I Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' CROSS- SECTION I BRANCH I NODE ID I SECTION NO. NVGD NAVD 1 1929 1988 V 9 SBRKFD 4027 9.20 12.78 10.98 9.87 14.56 13.45 14.56 13.13 10.08 16.71 13.66 16.71 V SBRKFU 4027 9.29 12.87 10.99 9.96 14.57 13.54 14.57 13.13 10.17 16.71 13.75 16.71 W 10 SBRKGD 9004 9.30 12.88 10.99 9.97 14.57 13.55 14.57 13.13 10.18 16.71 13.76 16.71 X SBRKG3 9004 9.42 13.00 11.01 10.10 14.59 13.68 14.59 13.13 10.31 16.71 13.89 16.71 SBRKG2 9005 9.54 13.12 11.03 10.23 14.61 13.81 14.61 13.13 10.44 16.71 14.02 16.71 Y OAKBRD 9010 9.53 13.11 11.03 10.23 14.61 13.81 14.61 13.14 10.44 16.72 14.02 16.72 Z OAKBRU 9012 9.60 13.18 11.04 10.29 14.62 13.87 14.62 13.14 10.51 16.72 14.09 16.72 SBRKGI 9014 9.67 13.25 11.05 10.37 14.63 13.95 14.63 13.14 10.58 16.72 14.16 16.72 AA SBRKGU 9021 9.75 13.33 11.07 10.46 14.65 14.04 14.65 13.14 10.68 16.72 14.26 16.72 AA 13 SBRKHD 9021 9.76 13.34 11.07 10.47 14.65 14.05 14.65 13.14 10.69 16.72 14.27 16.72 AB SBRKH2 9029 10.01 13.59 11.13 10.76 14.71 14.34 14.71 13.15 11.00 16.73 14.58 16.73 SBRKH3 9030 10.09 13.67 11.14 10.85 14.72 14.43 14.72 13.16 11.09 16.74 14.67 16.74 SBRKH4 9031 10.09 13.67 11.14 10.85 14.72 14.43 14.72 13.16 11.08 16.74 14.66 16.74 SBRKH5 9032 10.09 13.67 11.14 10.85 14.72 14.43 14.72 13.16 11.09 16.74 14.67 16.74 SBRKH6 9033 10.15 13.73 11.16 10.92 14.74 14.50 14.74 13.17 11.15 16.75 14.73 16.75 AC SBRKHU 9035 10.19 13.77 11.17 10.97 14.75 14.55 14.75 13.18 11.21 16.76 14.79 16.76 AC 14 SBRKID 9035 10.20 13.78 11.17 10.98 14.75 14.56 14.75 13.18 11.23 16.76 14.81 16.76 SBR KI1 9036 10.17 13.75 11.17 10.95 14.75 14.53 14.75 13.18 11.19 16.76 14.77 16.76 SBRK12 9039 10.27 13.85 11.19 11.07 14.77 14.65 14.77 13.19 11.31 16.77 14.89 16.77 AD SBRK13 9040 10.29 13.87 11.19 11.08 14.77 14.66 14.77 13.19 11.32 16.77 14.90 16.77 AE HDBRID 9043 10.39 13.97 11.21 11.17 14.79 14.75 14.79 13.20 11.41 16.78 14.99 16.78 AF SBRK14 9052 10.76 14.34 11.32 11.60 14.90 15.18 15.18 13.26 11.85 16.84 15.43 16.84 SBRK15 9053 10.78 14.36 11.32 11.62 14.90 15.20 15.20 13.27 11.88 16.85 15.46 16.85 SBRKJU 9055 10.80 14.38 11.33 11.65 14.91 15.23 15.23 13.27 11.91 16.85 15.49 16.85 16 SBRKJD 9055 10.80 14.38 11.32 11.63 14.90 15.21 15.21 13.27 11.88 16.85 15.46 16.85 SBR KJ 1 9056 10.79 14.37 11.33 11.65 14.91 15.23 15.23 13.27 11.90 16.85 15.48 16.85 AG SBRKJ2 9058 10.81 14.39 11.33 11.65 14.91 15.23 15.23 13.27 11.91 16.85 15.49 16.85 AH SBRKJ3 9065 10.93 14.51 11.37 11.81 14.95 15.39 15.39 13.30 12.07 16.88 15.65 16.88 Al SBRKJ4 9069 11.08 14.66 11.42 11.94 15.00 15.52 15.52 13.31 12.20 16.89 15.78 16.89 AJ SBRKJ5 9071 11.16 14.74 11.46 12.04 15.04 15.62 15.62 13.33 12.30 16.91 15.88 16.91 AK SBRKJU 9073 11.22 14.80 11.48 12.09 15.06 15.67 15.67 13.34 12.35 16.92 15.93 16.92 AK 17 SBRKKD 9073 11.23 14.81 11.48 12.10 15.06 15.68 15.68 13.34 12.35 16.92 15.93 16.92 AL SBRKKI 9075 11.23 14.81 11.48 12.10 15.06 15.68 15.68 13.34 12.35 16.92 15.93 16.92 K'S at le" 1-00781 Spnngbmk Crxk FEMA mmppingVlepon T5" FimRSpnngbmkHydnu1icsFm1.doc &9/06 R. W. Beck 3-3 Section 3 Table 8 (cont.) 10-Percent-Annual- Chance Flood Water - Surface Elevation (feet) 2-Percent-Annual-Chance Flood Water -Surface Elevation feet 1-Percent-Annual-Chance Flood Water -Surface Elevation feet NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA CROSS- Storage Conveyance Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' Storage Conveyance I Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' CROSS- SECTION BRANCH NODE ID SECTION NO. NVGD NAVD 1929 1988 AM JCKKKU 9Utb 11.2b 14.64 11.49 12.12 15.07 15.70 15.70 13.35 12.37 16.93 15.95 16.93 AM 18 SBRKLD 9078 11.26 14.84 11.49 12.12 15.07 15.70 15.70 13.35 12.37 16.93 15.95 16.93 AN SBRKLU 9079 11.29 14.87 11.50 12.14 15.08 15.72 15.72 13.35 12.39 16.93 15.97 16.93 AO 19 SBRKMD 9082 11.68 15.26 11.68 12.60 15.26 16.18 16.18 13.49 12.87 17.07 16.45 17.07 AP SBRKMI 9080 11.74 15.32 11.71 12.64 15.29 16,22 16.22 13.49 12.91 17.07 16.49 17.07 AQ SBRKMU 9081 11.77 15.35 11.73 12.65 15.31 16.23 16.23 13.50 12.92 17.08 16.50 17.08 AR 20 SBRKND 9102 11.85 15.43 11.77 12.77 15.35 16.35 16.35 13.56 13.05 17.14 16.63 17.14 AR SBRKNU 9102 11.85 15.43 11.77 12.77 15.35 16.35 16.35 13.56 13.06 17.14 16.64 17.14 AR 21 SBRKOD 9102 11.85 15.43 11.77 12.77 15.35 16.35 16,35 13.56 13.06 17.14 16.64 17.14 AS SBRKO2 9103 11.85 15.43 11.77 12.77 15.35 16.35 16.35 13.56 13.06 17.14 16.64 17.14 AT SBRKO1 9104 11.85 15.43 11.78 12.78 15.36 16.36 16.36 13.56 13.06 17.14 16.64 17.14 AU SBRKOU 9105 11.86 15.44 11.78 12.78 15.36 16.36 16.36 13.56 13.06 17.14 16.64 17.14 AU 23 SBRKPD 9105 11.86 15.44 11.78 12.78 15.36 16.36 16.36 13.56 13.06 17.14 16.64 17.14 AV SBRKPU 9106 11.87 15.45 11.79 12.78 15.37 16.36 16.36 13.56 13.06 17.14 16.64 17.14 AV 24 SBRKQD 9106 11.87 15.45 11.79 12.78 15.37 16.36 16.36 13.56 13.06 17.14 16.64 17.14 AW SBRKQU 9107 12.07 15.65 11.91 12.96 15.49 16.54 16.54 13.61 13.24 17.19 16.82 17.19 AW 25 SBRKRD 9107 12.10 15.68 11.92 12.98 15.50 16.56 16.56 13.63 13.25 17.21 16.83 17.21 AW SW34TH 9107 12.15 15.73 11.96 13.04 15.54 16.62 16.62 13.64 13.31 17.22 16.89 17.22 AX 26 SW34TH 9108 13.42 17.00 12.62 15.17 16.20 18.75 18.75 14.83 15.30 18.41 18.88 18.88 AY SBRKSI 9109 13.49 17.07 12.68 15.25 16.26 18.83 18.83 14.87 15.40 18.45 18.98 18.98 AZ SBRKLU 9110 13.60 17.18 12.77 15.37 16.35 18.95 18.95 14.93 15.52 18.51 19.10 19.10 AZ 27 SBRKTD 9110 13.60 17.18 12.77 15.37 16.35 18.95 18.95 14.93 15.52 18.51 19.10 19.10 BA SBRKT1 9111 13.68 17.26 12.84 15.46 16.42 19.04 19.04 14.98 15.62 18.56 19.20 19.20 BB SBRKTU 9112 13.89 17.47 13.03 15.68 16.61 19.26 19.26 15.10 15.87 18.68 19.45 19.45 BC 30 SBRKUD 9115 13.97 17.55 13.12 15.88 16.70 19.46 19.46 15.16 16.10 18.74 19.68 19.68 BD SW41ST 9114 14.09 17.67 13.25 16.03 16.83 19.61 19.61 15.24 16.26 18.82 19.84 19.84 BE 31 SW41ST 2076 15.31 18.89 14.16 17.56 17.74 21.14 21.14 16.52 17.67 20.10 21.25 21.25 SBRKVI 2077 15.33 18.91 14.19 17.57 17.77 21.15 21.15 16.54 17.68 20.12 21.26 21.26 3-4 R. W. Beck R&.U1d11-00781SpngbmkCreckFEMArenuppiq\Repor1sTFMAFiuMpringbwkHydndicsRm1doc 0/06 FLOOD PROFILES Table 8 (cont.) 10-Percent-Annual- Chance Flood Water - Surface Elevation (feet) 2-Percent-Annual-Chance Flood Water -Surface Elevation feet 1-Percent-Annual-Chance Flood Water -Surface Elevation feet NVGD 1929 NAVD 1988 NVGD 1929 1 NAVD 1988 FEMA CROSS- Storage Conveyance Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' Storage Conveyance Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' CROSS- SECTION BRANCH NODE ID SECTION NO. NVGD NAVD 1929 1988 68RKV2 2078 15.36 18.94 14.23 17.6U 17.81 21.18 21.18 16.56 17.71 Z0.14 21.29 21.29 SBRKV4 2080 15.37 18.95 14.24 17.61 17.82 21.19 21.19 16.57 17.73 20.15 21.31 21.31 SBRKV5 2081 15.43 19.01 14.31 17.66 17.89 21.24 21.24 16.62 17.79 20.20 21.37 21.37 SBRKV6 2082 15.45 19.03 14.34 17.68 17.92 21.26 21.26 16.63 17.81 20.21 21.39 21.39 SBRKV7 2083 15.46 19.04 14.36 17.69 17.94 21.27 21.27 16.64 17.82 20.22 21.40 21.40 SBRKVU 2085 15.50 19.08 14.41 17.73 17.99 21.31 21.31 16.67 17.87 20.25 21.45 21.45 33 SBRKWD 2085 15.50 19.08 14.41 17.73 17.99 21.31 21.31 16.67 17.87 20.25 21.45 21.45 BF SBRKWI 2086 15.52 19.10 14.43 17.74 18.01 21.32 21.32 16.68 17.88 20.26 21.46 21.46 SBRKW2 2087 15.52 19.10 14.44 17.73 18.02 21.31 21.31 16.68 17.87 20.26 21.45 21.45 SBRKW3 2088 15.54 19.12 14.47 17.75 18.05 21.33 21.33 16.69 17.89 20.27 21.47 21.47 SBRKW4 2089 15.56 19.14 14.49 17.77 18.07 21.35 21.35 16.71 17.91 20.29 21.49 21.49 SBRKW5 2090 15.58 19.16 14.52 17.79 18.10 21.37 21.37 16.73 17.93 20.31 21.51 21.51 SBRKW6 2091 15.60 19.18 14.54 17.81 18.12 21.39 21.39 16.74 17.95 20.32 21.53 21.53 SBRKW7 2092 15.63 19.21 14.58 17.84 18.16 21.42 21.42 16.77 17.98 20.35 21.56 21.56 BG SW43RD 2093 15.55 19.13 14.48 17.75 18.06 21.33 21.33 16.70 17.89 20.28 21.47 21.47 P-9 CHANNEL CA 450 P9CHABAD 8040 11.23 14.81 11.48 12.10 15.06 15.68 15.68 13.34 12.35 16.92 15.93 16.92 CB P9CHANA3 8041 11.30 14.88 11.50 12.14 15.08 15.72 15.72 13.35 12.39 16.93 15.97 16.93 CC P9CHANA2 8042 11.30 14.88 11.50 12.14 15.08 15.72 15.72 13.35 12.39 16.93 15.97 16.93 CD P9CHANA1 8043 11.31 14.89 11.50 12.14 15.08 15.72 15.72 13.35 12.39 16.93 15.97 16.93 CE P9CHANAU 8044 11.34 14.92 11.51 12.16 15.09 15.74 15.74 13.35 12.41 16.93 15.99 16.93 CF 45 P9CHAND 8050 11.53 15.11 11.61 12.25 15.19 15.83 15.83 13.37 12.48 16.95 16.06 16.95 CG P9CHANU 8050 11.54 15.12 11.61 12.26 15.19 15.84 15.84 13.37 12.48 16.95 16.06 16.95 CH 461 P9CHANBU 8045 11.58 15.16 11.63 12.33 15.21 15.91 15.91 13.42 12.56 17.00 16.14 17.00 P9CHANBD 8045 11.58 15.16 11.63 12.33 15.21 15.91 15.91 13.42 12.56 17.00 16.14 17.00 46 P9CHANBD 8045 11.58 15.16 11.63 12.33 15.21 15.91 15.91 13.42 12.56 17.00 16.14 17.00 CI P9CHAN13U 8046 12.69 16.27 12.31 13.10 15.89 16.68 16.68 13.47 13.18 17.05 16.76 17.05 47 P9CHANCD 8046 12.69 16.27 12.31 13.10 15.89 16.68 16.68 13.47 13.18 17.05 16.76 17.05 CJ P9CHANC2 8047 12.69 16.27 12.31 13.10 15.89 16.68 16.68 13.47 13.18 17.05 16.76 17.05 CK P9CHANC1 8048 12.71 16.29 12.33 13.12 15.91 16.70 16.70 13.47 13.20 17.05 16.78 17.05 CL P9CHANCU 8049 12.92 16.50 12.54 13.35 16.12 16.93 16.93 13.54 13.42 17.12 17.00 17.12 CM 81 P9CHAN 9009 13.49 17.07 12.85 14.38 16.43 17.96 17.96 14.32 14.56 17.90 18.14 18.14 RiSeanle111.00781 Springbmok Creek FEMA m=ppinglRepom\FEMA FiuhSpringbmokHydmulicsFinal.dac 819I06 R. W. Beck 3-5 Section 3 Table 8 (cont.) 10-Percent-Annual- Chance Flood Water - Surface Elevation (feet) 2-Percent-Annual-Chance Flood Water -Surface Elevation feet 1-Percent-Annual-Chance Flood Water -Surface Elevation feet NVGD 1929 NAVD 1988 NVGD 1929 1 NAVD 1988 FEMA CROSS- Storage Conveyance Scenario Scenario Storage Conveyance Water Surface Scenario Scenario Profile' Storage Conveyance I Scenario Scenario I Storage Conveyance Water Surface Scenario Scenario Profile' CROSS- SECTION BRANCH NODE ID SECTION NO. NVGD NAVD 1929 1988 CN 9U13 13.49 17.07 12.8b 14.38 16.43 17.95 17.96 14.31 14.56 17.89 18.14 18.14 80 P9CHAN 9008 13.78 17.36 13.00 14.94 16.58 18.52 18.52 14.77 15.17 18.35 18.75 18.75 9008 13.78 17.36 13.00 14.94 16.58 18.52 18.52 14.77 15.17 18.35 18.75 18.75 BYPASS CHANNEL UNDER 1.405 Q 64 BY405BD 4028 8.45 12.03 10.89 9.09 14.47 12.67 14.47 13.12 9.29 16.70 12.87 16.70 S BY405BU 4029 8.80 12.38 10.92 9.43 14.50 13.01 14.50 13.12 9.63 16.70 13.21 16.70 S 63 BY405AD 4029 8.46 12.04 10.89 9.09 14.47 12.67 14.47 13.12 9.29 16.70 12.87 16.70 U BY405AU 4026 8.44 12.02 10.89 9.08 14.47 12.66 14.47 13.12 9.27 16.70 12.85 16.70 PANTHER CREEK WETLAND F 13 14.82 18.40 14.74 15.99 18.32 19.57 19.57 15.24 16.18 18.82 19.76 19.76 F21 13.94 17.52 13.34 14.98 16.92 18.56 18.56 14.81 15.21 18.39 18.79 18.79 F31 13.94 17.52 13.34 14.98 16.92 18.56 18.56 14.81 15.21 18.39 18.79 18.79 'Water surface profile was determined by using the higher of the storage or conveyance scenario water surface elevations 3-6 R. W. Beck R: Se&tde\I 1-00781 Springbmok Crock FEMA rcrosppigg RcporUTEMA FiuMpringbm 1LHydmulicsFim1.doc 8NI06 FLOOD PROFILES Once the new updated flood profiles were developed, they were checked to see if they reasonably tie into the existing Flood Insurance Study Mapping at the study boundaries. The two areas where this mapping update ties into upstream floodplain mapping areas include Springbrook Creek at SW 43rd Street (the city limits) and Rolling Hills Creek where it enters the Panther Creek Wetland. At both locations, the comparison was made at the upstream ends of the study reach, which are both at the downstream side of a culvert (i.e., the SW 43rd Street culvert and the Rolling Hills crossing of I-405). The resulting flood profiles at the boundaries of the study reach correspond fairly well with the existing flood profiles. At SW 43rd Street the new and prior base flood elevation in NAVD 1988 vertical datum are 21.47 feet and 21.18 feet, respectively. At the Rolling Hills discharge to the Panther Creek Wetland, the new and prior base flood elevations in NAVD 1988 vertical datum are 19.76 feet and 19.58 feet, respectively. The new mapping results compare well with the current FEMA base flood elevations at these locations. At Rolling Hills Creek the FEQ model extends beyond the study reach for the current mapping update and it was noted that results at the upstream of the model do not match as closely with the current regulated base flood elevation for Rolling Hills Creek. The portion of the FEQ model for Rolling Hills Creek includes a set of parallel culverts upstream of the Panther Creek wetlands as well as a short channel reach upstream of I-405. The simulated base flood elevations upstream of I-405 (outside of the study reach) are considerably lower than the existing base flood elevation. This is because the previous hydraulic analysis was conducted prior to the addition of the second parallel culvert under I-405 which resulted in reduced headloss and lower water surface elevations than the prior hydraulic analysis. Because this was upstream of the current study reach, reconciling this difference was considered is beyond the scope of this study. However, future re -mapping of Rolling Hills Creek Floodplain (Panel No. 977 and 979) upstream of I-405 is recommended. The peak flow results presented in Table 9. The resulting peak flows as modeled by FEQ are quite similar to the hydrologic HSPF modeling results. The 100-year peak flow as established by the HSPF frequency analysis for the Conveyance event is 1307 cfs compared to the FEQ simulation of 1197 (peak BRPS forebay inflow). This difference (8 percent) can be attributed to the inherent modeling differences (steady state versus unsteady state) as well as likely small differences between the HSPF characterizations of the system conveyance system compared with FEQ (i.e. HSPF use of HEC-RAS to develop F-TABLES vs. the FEQ simulation of the system). RASeatt1e\11-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydmulicsFinal.doc 8/9i06R. W. Beck 3-3 Section 4 FLOODPLAIN MANAGEMENT APPLICATIONS 4.1 Floodplain Boundaries The floodplain boundary for the base flood event is shown in Exhibit B. The floodplain map, consistent with FEMA mapping (formatting) standards, has also been provided in digital form in the digital appendix, Appendix C. The base map was prepared by the City of Renton, Washington based on aerial photographs taken in 1999. This is the most recent topographic mapping available for the study reach. Note that the floodplain boundaries are confined more closely to the channel than in the previous study. This is due to the decrease in base flood water surface elevations as was discussed -in Section 4. In general, the extent of the floodplain boundaries was developed by using the base flood elevations and comparing them to the 1999 topography to identify the extent of floodplain. In certain areas, development had occurred after 1999 and for these, updated topographic information (such as a developer's grading plans) were used instead of the 1999 topography. These locations are identified on the floodplain map. . In regard to the floodplain designation of wetland 12, as noted in Section 3, a series of detention pond cells and a wetland were assumed to be combined and represented by a single level pool reservoir to simplify the 1996 modeling effort. In reality, the southerly crescent shaped wetland and the north series of ponds are separate. Also, the north series of ponds is connected to Springbrook Creek with a flap gate to reduce the potential for Springbrook Creek flows to back up into the pond system. For the determination of the floodplain, it was assumed that the water levels in these ponds would match the base flood elevation of Springbrook Creek where they connect to the creek. 4.2 Floodway Boundaries The results of the floodway analysis are tabulated in Table 10 and shown in Exhibit B. The floodway boundary developed in this study was determined by modeling scenarios that included filling in the floodplain (overbank areas on both sides of the channel and wetland areas) such that it causes no more than a 1-foot rise in the water surface profile. The floodway as established by the existing FIRM was used as an initial trail floodway for this study. The result was that simulated water surface elevations along the creek were well above the 1-foot rise threshold. R:\Seatde\l 1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Section 4 Table 10 Floodway Analysis Results FLOODING SOURCE FLOODWAY 1-Percent-Annual-Chance Flood Water -Surface Elevation Floodway Water Levels feet MEAN NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA VELOCITY Water CROSS- CROSS- DISTANCE SECTION NODE ID SECTION NO. (Feet) SECTION AREA (Feet Per WIDTH (Square Feet) Second) Storage Conveyance Scenario Scenario Storage Conveyance Surface Scenario Scenario Profilet6 Storage Conveyance Scenario Scenario Storage Conveyance Floodway Scenario Scenario Limits16 Difference (feet)" A YSrUKUYU ZUSU 0 itt 2114 U.6 13.11 4.09 16.69 7.67 16.69 13.66 4.10 17.44 7.66 11.44 U.15 PSFORB10 2051 170 260 1581 1.1 13.11 4.09 16.69 7.67 16.69 13.86 4.09 17.44 7.67 17.44 0.75 B PSFORBY9 2052 225 601 ' 1596 1.0 13.11 4.09 16.69 7.67 16.69 13.86 4.09 17.44 7.67 17.44 0.75 C PSFORBY8 2053 505 688' 845 1.8 13.11 4.07 16.69 7.65 16.69 13.86 4.08 17.44 7.66 17.44 0.75 D PSFORBY7 2054 635 268' 515 2.9 13.11 4.11 16.69 7.69 16.69 13.86 4.12 17.44 7.70 17.44 0.75 PSFORBY6 2055 825 500' 1070 1.3 13.11 4.27 16.69 7.85 16.69 13.86 4.29 17.44 7.87 17.44 0.75 E PSFORBY5 2056 1035 459' 1115 1.2 13.11 4.31 16.69 7.89 16.69 13.86 4.33 17.44 7.91 17.44 0.75 F PSFORBY4 2057 1305 278' 503 2.6 13.11 4.31 16.69 7.89 16.69 13.86 4.33 17.44 7.91 17.44 0.75 G PSFORBY3 2058 1640 541' 1589 0.8 13.11 4.49 16.69 8.07 16.69 13.86 4.53 17.44 8.11 17.44 0.75 PSFORBY2 2059 1715 900' 3273 0.4 13.11 4.51 16.69 8.09 16.69 13.86 4.54 17.44 8.12 17.44 0.75 PSFORBYI 2060 1835 550' 1619 0.8 13.11 4.50 16.69 8.08 16.69 13.86 4.53 17.44 8.11 17.44 0.75 PSFORBYU 2061 1950 315' 765 1.7 13.11 4.48 16.69 8.06 16.69 13.86 4.51 17.44 8.09 17.44 0.75 H SBRKAD 4010 2000 74 165 7.9 13.11 4.63 16.69 8.21 16.69 13.86 4.68 17.44 8.26 17.44 0.75 1 SBRKAU 4012 2220 60 314 4.1 13.11 6.54 16.69 10.12 16.69 13.86 6.63 17.44 10.21 17.44 0.75 1 SBRKBD 4012 2220 60 281 4.0 13.11 6.76 16.69 10.34 16.69 13.86 6.91 17A4 10.49 17.44 0.75 J SBRKBI 4014 2537 402 218 5.2 13.11 7.41 16.69 10.99 16.69 13.86 7.53 17.44 11.11 17.44 0.75 K SBRKBU 4015 2840 76 451 2.5 13.11 7.99 16.69 11.57 16.69 13.86 8.50 17.44 12.08 17.44 0.75 K SBRKCD 4015 2840 76 451 2.5 13.11 7.99 16.69 11.57 16.69 13.86 8.50 17.44 12.08 17.44 0.75 L SBRKC4 4016 3266 67 468 2.4 13.11 8.30 16.69 11.88 16.69 13.86 8.76 17.44 12.34 17.44 0.75 M SBRKC3 4018 3754 603 396 2.8 13.11 8.61 16.69 12.19 16.69 13.86 9.05 17.44 12.63 17.44 0.75 N SBRKC2 4019 4280 704 440 2.5 13.11 8.92 16.69 12.50 16.69 13.87 9.57 17.45 13.15 17.45 0.75 0 SBRKCI 4020 4669 61 385 2.9 13.11 9.13 16.69 12.71 16.69 13.87 9.89 17.45 13.47 17.45 0.76 P SBRKCU 2074 4728 60, 583 1.9 13.11 9.23 16.69 12.81 16.69 13.88 10.01 17.46 13.59 17.46 0.77 Q SBRKDD 4028 4961 64 6 551 0.7 13.12 9.29 16.70 12.87 16.70 13.90 10.05 17.48 13.63 17.48 0.78 R SBRKDI 4021 5077 39 283 1.4 13.12 9.27 16.70 12.85 16.70 13.89 10.03 17.47 13.61 17.47 0.78 T SBRKDU 4022 5476 30 46 8.7 13.12 9.77 16.70 13.35 16.70 13.93 10.41 17.51 13.99 17.51 0.80 T SBRKED 4022/4024 5476 100 46 8.7 13.12 9.77 16.70 13.35 16.70 13.93 10.41 17.51 13.99 17.51 0.80 U SBRKEU 4025/4026 5560 727 191 2.1 13.13 10.08 16.71 13.66 16.71 13.95 10.65 17.53 14.23 17.53 0.82 V SBRKFD 4027 5564 60' 359 3.1 13.13 10.08 16.71 13.66 16.71 13.95 10.65 17.53 14.23 17.53 0.82 V SBRKFU 4027 5620 60' 367 3.0 13.13 10.17 16.71 13.75 16.71 13.95 10.78 17.53 14.36 17.53 0.82 W SBRKGD 9004 5682 59 340 3.3 13.13 10.18 16.71 13.76 16.71 13.96 10.79 17.54 14.37 17.54 0.83 X SBRKG3 9004 5777 59 345 3.2 13.13 10.31 16.71 13.89 16.71 13.96 10.89 17.54 14.47 17.54 0.83 SBRKG2 9005 5850 59 466 2.4 13.13 10.44 16.71 14.02 16.71 13.98 11.03 17.56 14.61 17.56 0.84 Y OAK8RD 9010 5939 59 408 2.7 13.14 10.44 16.72 14.02 16.72 13.97 11.00 17.55 14.58 17.55 0.84 Z OAKBRU 9012 6039 58 422 2.7 13.14 10.51 16.72 14.09 16.72 13.98 11.08 17.56 14.66 17.56 0.84 4-2 R. W. Beck R:1S-1,41.00791 Sp6rgbrook Crmk FEMA mmapping\AepoMTEMA FimASpringbrookHyd... 1 eFirul docg/9/06 FLOODPLAIN MANAGEMENT APPLICATIONS Table 10 (cont.) FLOODING SOURCE FLOODWAY 1-Percent-Annual-Chance Flood Water -Surface Elevation Floodwa Water Levels feet MEAN NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA VELOCITY Water CROSS- CROSS- DISTANCE SECTION NODE ID SECTION NO. (Feet) SECTION AREA (Feet Per WIDTH (Square Feet) Second) Storage Conveyance Scenario Scenario Storage Conveyance Surface Scenario Scenario Profile" Storage Conveyance Scenario Scenario Storage Conveyance Floodway Scenario Scenario Limits" Difference (feet)" SoRNG! 9014 6139 50 480 2.3 13.14 1U.56 16.72 14.16 16.72 13.99 11.16 17.57 14.74 17.57 0.85 AA SBRKGU 9021 6489 56 413 2.7 13.14 10.68 16.72 14.26 16.72 13.99 11.25 17.57 14.83 17.57 0.85 AA SBRKHD 9021 6489 56 403 2.7 13.14 10.69 16.72 14.27 16.72 14.00 11.26 17.58 14.84 17.58 0.85 AB SBRKH2 9029 6889 54 384 2.8 13.15 11.00 16.73 14.58 16.73 14.02 11.52 17.60 15.10 17.60 0.87 SBRKH3 9030 6939 54 459 2.4 13.16 11.09 16.74 14.67 16.74 14.03 11.59 17.61 15.17 17.61 0.86 SBRKH4 9031 6989 54 434 2.5 13.16 11.08 16.74 14.66 16.74 14.03 11.59 17.61 15.17 17.61 0.87 SBRKH5 9032 7039 54 426 2.6 13.16 11.09 16.74 14.67 16.74 14.03 11.59 17.61 15.17 17.61 0.87 SBRKH6 9033 7089 53 445 2.4 13.17 11.15 16.75 14.73 16.75 14.03 11.64 17.61 15.22 17.61 0.86 AC SBRKHU 9035 7189 53 506 2.1 13.18 11.21 16.76 14.79 16.76 14.04 11.71 17.62 15.29 17.62 0.86 AC SBRKHD 9035 7189 53 502 2.0 13.18 11.23 16.76 14.81 16.76 14.04 11.73 17.62 15.31 17.62 0.86 SBRKII 9036 7239 53 395 2.6 13.18 11.19 16.76 14.77 16.76 14.04 11.69 17.62 15.27 17.62 0.86 SBRK12 9039 7389 52 379 2.7 13.19 11.31 16.77 14.89 16.77 14.04 11.75 17.62 15.33 17.62 0.85 AD SBRK13 9040 7439 52 387 2.6 13.19 11.32 16.77 14.90 16.77 14.05 11.79 17.63 15.37 17.63 0.86 AE HDBRID 9043 7589 51 335 3.0 13.20 11.41 16.78 14.99 16.78 14.06 11.90 17.64 15.48 17.64 0.86 AF SBRK14 9052 8039 56 540 1.9 13.26 11.85 16.84 15.43 16.84 14.11 12.32 17.69 15.90 17.69 0.85 SBRK15 9053 8089 57 513 2.0 13.27 11.88 16.85 15.46 16.85 14.12 12.34 17.70 15.92 17.70 0.85 SBRKIU 9055 8189 57 511 2.0 13.27 11.91 16.85 15.49 16.85 14.12 12.37 17.70 15.95 17.70 0.85 SBRKJD 9055 8189 57 510 2.0 13.27 11.88 16.85 15.46 16.85 14.12 12.37 17.70 15.95 17.70 0.85 SBRKJ1 9056 8239 57 467 2.1 13.27 11.90 16.85 15.48 16.85 14.12 12.35 17.70 15.93 17.70 0.85 AG SBRKJ2 9058 8339 59 395 2.5 13.27 11.91 16.85 15.49 16.85 14.12 12.36 17.70 15.94 17.70 0.84 AH SBRKJ3 9065 8689 63 386 2.6 13.30 12.07 16.88 15.65 16.88 14.14 12.51 17.72 16.09 17.72 0.84 Al SBRKJ4 9069 8889 65 408 2.4 13.31 12.20 16.89 15.78 16.89 14.16 12.64 17.74 16.22 17.74 0.84 AJ SBRKJ5 9071 8989 65 469 2.1 13.33 12.30 16.91 15.88 16.91 14.16 12.70 17.74 16.28 17.74 0.83 AK SBRKJU 9073 9089 929 513 1.9 13.34 12.35 16.92 15.93 16.92 14.17 12.78 17.75 16.36 17.75 0.83 AK SBRKKD 9073 9089 929 9 483 1.8 13.34 12.35 16.92 15.93 16.92 14.17 12.78 17.75 16.36 17.75 0.83 AL SBRKK1 9075 9189 617 495 1.8 13.34 12.35 16.92 15.93 16.92 14.17 12.78 17.75 16.36 17.75 0.83 AM SBRKKU 9078 9491 610 544 1.6 13.35 12.37 16.93 15.95 16.93 14.18 12.79 17.76 16.37 17.76 0.83 AM SBRKLD 9078 9491 610 9 544 1.6 13.35 12.37 16.93 15.95 16.93 14.18 12.79 17.76 16.37 17.76 0.83 AN SBRKLU 9079 9691 572 a 446 1.9 13.35 12.39 16.93 15.97 16.93 14.18 12.81 17.76 16.39 17.76 0.83 AO SBRKMD 9082 9766 4569 509 1.7 13.49 12.87 17.07 16.45 17.07 14.29 13.25 17.87 16.83 17.87 0.80 AP SBRKMI 9080 10092 326 489 1.7 13.49 12.91 17.07 16.49 17.07 14.29 13.28 17.87 16.86 17.87 0.80 AQ SBRKMU 9081 10213 318 9 557 1.5 13.50 12.92 17.08 16.50 17.08 14.29 13.29 17.87 16.87 17.87 0.80 AR SBRKND 9102 10309 216310 620 1.4 13.56 13.05 17.14 16.63 17.14 14.35 13.43 17.93 17.01 17.93 0.80 AR SBRKNU 9102 10366 216310 620 1.3 13.56 13.06 17.14 16.64 17.14 14.35 13.43 17.93 17.01 17.93 0.80 3.58 AR SBRKOD 9102 10366 216310 616 1.3 13.56 13.06 17.14 16.64 17.14 14.35 13.43 17.93 17.01 17.93 0.80 AS SBRK02 9103 10435 225610 597 1.4 13.56 13.06 17.14 16.64 17.14 14.35 13.43 17.93 17.01 17.93 0.80 AT SBRK01 9104 10937 228110 570 1.4 13.56 13.06 17.14 16.64 17.14 14.36 13.43 17.94 17.01 17.94 0.80 AU SBRKOU 9105 11344 215110 428 1.8 13.56 13.06 17.14 16.64 17.14 14.36 13.43 17.94 17.01 17.94 0.80 R:\Sun1e\11.00781 Sp-gb-k Creak FEMA.-pp,g\Repons\FEMA Fm&1\Spnngb=kHydnu1icsFtm1 clocfl'9106 R. W. Beck 4-3 Section 4 Table 10 (cont.) FLOODING SOURCE FLOODWAY 1-Percent-Annual-Chance Flood Water -Surface Elevation Floodwa Water Levels feet MEAN NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA VELOCITY Water CROSS- CROSS- DISTANCE SECTION NODE ID SECTION NO. (Feet) SECTION AREA (Feet Per WIDTH (Square Feet) Second) Storage Conveyance Scenario Scenario Storage Conveyance Surface Scenario Scenario Profile" Storage Conveyance Scenario Scenario Storage Conveyance Floodway Scenario Scenario Limits" Difference (feet)" AU SBRKPD 9105 11344 215110 427 1.8 13.56 13.06 17.14 16.64 17.14 14.36 13.43 17.94 17.01 17.94 0.80 AV SBRKPU 9106 11882 63 306 2.7 13.56 13.06 17.14 16.64 17.14 14.35 13.42 17.93 17.00 17.93 0.80 AV SBRKQD 9106 11882 63 306 2.7 13.56 13.06 17.14 16.64 17.14 14.35 13.42 17.93 17.00 17.93 0.80 AW SBRKQU 9107 12370 63 304 2.8 13.61 13.24 17.19 16.82 17.19 14.39 13.58 17.97 17.16 17.97 0.78 SBRKRD 9107 12370 63 316 2.4 13.63 13.25 17.21 16.83 17.21 14.40 13.60 17.98 17.18 17.98 0.77 SW34TH 9107 12502 63 320 2.4 13.64 13.31 17.22 16.89 17.22 14.41 13.65 17.99 17.23 17.99 0.77 AX SW34TH 9108 12661 63 504 2.2 14.83 15.30 18.41 18.88 18.88 15.14 15.35 18.72 18.93 18.93 0.05 AY SBRKSI 9109 13061 59 492 2.3 14.87 15.40 18.45 18.98 18.98 15.18 15.44 18.76 19.02 19.02 0.04 AZ SBRKSU 9110 13661 54 449 2.5 14.93 15.52 18.51 19.10 19.10 15.23 15.58 18.81 19.16 19.16 0.06 AZ SBRKTD 9110 13661 54 449 2.5 14.93 15.52 18.51 19.10 19.10 15.23 15.58 18.81 19.16 19.16 0.06 BA SBRKTI 9111 14061 50 358 3.1 14.98 15.62 18.56 19.20 19.20 15.26 15.68 18.84 19.26 19.26 0.06 BB SBRKTU 9112 14637 42 369 3.0 15.10 15.87 18.68 19.45 19.45 15.36 15.91 18.94 19.49 19.49 0.04 BC SBRKUD 9115 14710 4111 343 3.3 15.16 16.10 18.74 19.68 19.68 15.43 16.14 19.01 19.72 19.72 0.04 BD SW41 ST 9114 14970 43 385 2.9 15.24 16.26 18.82 19.84 19.84 15.51 16.34 19.09 19.92 19.92 0.08 BE SW41ST 2076 15235 56 468 2.3 16.52 17.67 20.10 21.25 21.25 16.79 17.69 20.37 21.27 21.27 0.02 SBRKV1 2077 15335 62 558 1.9 16.54 17.68 20.12 21.26 21.26 16.81 17.73 20.39 21.31 21.31 0.05 SBRKV2 2078 15435 69 615 1.7 16.56 17.71 20.14 21.29 21.29 16.83 17.77 20.41 21.35 21.35 0.05 SBRKV4 2080 15535 75 560 1.9 16.57 17.73 20.15 21.31 21.31 16.84 17.78 20.42 21.36 21.36 0.05 SBRKV5 2081 15735 88 685 1.6 16.62 17.79 20.20 21.37 21.37 16.88 17.84 20.46 21.42 21.42 0.06 SBRKV6 2082 15835 88 742 1.4 16.63 17.81 20.21 21.39 21.39 16.89 17.86 20.47 21.44 21.44 0.06 SBRKV7 2083 15935 88 732 1.5 16.64 17.82 20.22 21.40 21.40 16.90 17.88 20.48 21.46 21.46 0.05 SBRKVU 2085 16135 88 610 1.7 16.67 17.87 20.25 21.45 21.45 16.92 17.91 20.50 21.49 21.49 0.04 SBRKWD 2085 16135 88 605 1.7 16.67 17.87 20.25 21.45 21.45 16.92 17.91 20.50 21.49 21.49 0.05 BF SBRKWI 2086 16235 88 514 2.1 16.68 17.88 20.26 21.46 21.46 16.93 17.92 20.51 21.50 21.50 0.04 SBRKW2 2087 16335 88 656 1.6 16.68 17.87 20.26 21.45 21.45 16.94 17.94 20.52 21.52 21.52 0.07 SBRKW3 2088 16435 88 672 1.6 16.69 17.89 20.27 21.47 21.47 16.96 17.96 20.54 21.54 21.54 0.07 SBRKW4 2089 16535 88 627 1.7 16.71 17.91 20.29 21.49 21.49 16.97 17.97 20.55 21.55 21.55 0.06 SBRKW5 2090 16635 88 629 1.7 16.73 17.93 20.31 21.51 21.51 16.98 17.99 20.56 21.57 21.57 0.06 SBRKW6 2091 16735 88 620 1.7 16.74 17.95 20.32 21.53 21.53 16.99 18.01 20.57 21.59 21.59 0.06 SBRKW7 2092 16835 88 646 1.6 16.77 17.98 20.35 21.56 21.56 17.01 18.04 20.59 21.62 21.62 0.06 BG SW43RD 2093 16935 6012 299 3.5 16.70 17.89 20.28 21.47 21.47 16.95 17.94 20.53 21.52 21.52 0.05 CA P9CHABAD 8040 60 t3 32 4.5 13.34 12.35 16.92 15.93 16.92 14.17 12.78 17.75 16.36 17.75 0.83 CB P9CHANA3 8041 420 60 t3 183 0.8 13.35 12.39 16.93 15.97 16.93 14.18 12.82 17.76 16.40 17.76 0.83 CC P9CHANA2 8042 500 6013 169 0.9 13.35 12.39 16.93 15.97 16.93 14.18 12.82 17.76 16.40 17.76 0.83 CD P9CHANA1 8043 550 6013 165 0.9 13.35 12.39 16.93 15.97 16.93 14.18 12.82 17.76 16.40 17.76 0.83 4-4 R. W. Beck R:1SuMcl 1-00 81 s rin brook Cmck FEMA mma P g PPingVteponsffMA FirmlSp6ngbrookHydrauliuFinal.dagN/06 FLOODPLAIN MANAGEMENT APPLICATIONS Table 10 (cont.) FLOODING SOURCE FLOODWAY 1-Percent-Annual-Chance Flood Water -Surface Elevation Floodwa Water Levels feet MEAN NVGD 1929 NAVD 1988 NVGD 1929 NAVD 1988 FEMA VELOCITY Water CROSS- CROSS- DISTANCE SECTION AREA (Feet Per Storage Conveyance Storage Conveyance Surface Storage Conveyance Storage Conveyance Floodway Difference SECTION NODE ID SECTION NO. (Feet) CE P9CHANell 8044 01n WIDTH (Square Feet) Second) nn Scenario Scenario Srio Scenario Profile7. cena Scenario Scenario Scenario Scenario Limits's (feet)7° -- _-........-- --,� ho.oa Ic.gi 16.93 15.99 16.93 14.18 12.83 17.76 16.41 17.76 0.83 CF P9CHAND 8050 896 9013 293 0.5 13.37 12.48 16.95 16.06 16.95 14.18 12.88 17.76 16.46 17.76 0.81 CG P9CHANU 8050 947 9013 254 0.6 13.37 12.48 16.95 16.06 16.95 14.18 12.88 17.76 16.46 17.76 0.81 CH P9CHANBU 8045 1061 53 153 0.9 13.42 12.56 17.00 16.14 17.00 14.21 12.96 17.79 16.54 17.79 0.79 P9CHANBD 8045 1066 53 153 0.9 13.42 12.56 17.00 16.14 17.00 14.21 12.96 17.79 16.54 17.79 0.79 P9CHANBD 8045 1066 53 42 3.4 13.42 12.56 17.00 16.14 17.00 14.21 13.40 17.79 16.98 17.79 0.79 Cl P9CHANBU 8046 1110 60 26 5.5 13.47 13.18 17.05 16.76 17.05 14.22 12.96 17.80 16.54 17.80 0.75 P9CHANCD 8046 1110 60 220 0.7 13.47 13.18 17.05 16.76 17.05 14.22 13.40 17.80 16.98 17.80 0.75 CJ P9CHANC2 8047 1545 60 204 0.7 13.47 13.18 17.05 16.76 17.05 14.23 13.52 17.81 17.10 17.81 0.75 CK P9CHANC1 8048 2075 60 184 0.8 13.47 13.20 17.05 16.78 17.05 14.23 13.72 17.81 17.30 17.81 0.76 CL P9CHANCU 8049 2292 40 105 1.4 13.54 13.42 17.12 17.00 17.12 14.30 13.96 17.88 17.54 17.88 0.76 CM P9CHAN 9009 2391 40 248 0.5 14.32 14.56 17.90 18.14 18.14 14.84 14.83 18.42 18.41 18.42 0.28 CN 9013 2492 40 218 0.5 14.31 14.56 17.89 18.14 18.14 14.84 14.83 18.42 18.41 18.42 0.29 P9CHAN 9008 0 14 659 0.2 14.77 15.17 18.35 18.75 18.75 15.28 15.37 18.86 18.95 18.95 0.20 9008 11 14 302 0.4 14.77 15.17 18.35 18.75 18.75 15.28 15.37 18.86 18.95 18.95 0.20 O BY405BD 4028 64 a 489 1.5 13.12 9.29 16.70 12.87 16.70 13.90 10.03 17.48 13.61 17.48 0.78 S BY405BU 4029 89 309 2.3 13.12 9.63 16.70 13.21 16.70 13.90 10.32 17.48 13.90 17.48 0.78 S BY405AD 4029 89 311 2.3 13.12 9.29 16.70 12.87 16.70 13.91 10.01 17.49 13.59 17,49 0.79 U BY405AU 4026 46 186 3.9 13.12 9.27 16.70 12.85 16.70 13.90 10.05 17.48 13.63 17.48 0.79 F13 17 15.27 16.18 18.85 19.76 19.76 15.42 16.30 19.00 19.88 19.88 0.12 F21 17 14.81 15.21 18.39 18.79 18.79 15.31 15.42 18.89 19.00 19.00 0.21 F31 17 14.81 15.21 18.39 18.79 18.79 15.31 15.42 18.89 19.00 19.00 0.21 Nobs: ' Black River Pump Station Forebay 11 Width was 44 feet in previous FEMA study. However, the floociplain width only 41 feet wide. ° Width was 26 feet in previous FEMA study. However, the width was widened in order to span the active channel. 11 Width was 88 feet in previous FEMA study. However, the floodplain width only 60 feet wide. ° Width was 37 feet in previous FEMA study However, the width was widened In order to span the activa channel. 11 Cme9 section includes wetland 4 ' NO was 48 feat in previous FEMA study. However, the width was widened in order to span the active channel. 14 Cross section includes wetland 11 s Width was 11 reel in previous FEMA study. However, the width was widened in order to span the active channel. 15 Storage Scenario water surface elevation or Conveyance Scenario water surface elevation, which ever is higher. ° Width was 25 feet in previous FEMA study. However, the width was widened In order to apes the active channel. 16 The increase in water surface elevation as the result or the floodway anaoacMient 1 Width was 28 feet in previous FEMA study. However, the width was widened in order to span the active channel. hr Freenodes ° Width was 24 feet in previous FEMA study. However, the width was widened in order to span the active channel. ° Cross section Includes wetland 4 10 Cross section includes wetlands 6, 7a and 11, R:1,Sum"iI GMI Sprirhgb-kCrxk FEMA.-ppingUteporu\FEMA FihwhSprin6brwkHydnulicoFiml.dwN9r06 R. W. Beck 4-5 FLOODPLAIN MANAGEMENT APPLICATIONS The prior FEMA floodway boundaries were found not acceptable for two primary reasons. The first reason is that the previous FEMA study employed steady state modeling that did not consider pumping restrictions when the Green River is at flood stage. The prior floodway boundary was generally defined along the banks of Springbrook Creek and did not include any significant overbank areas or wetlands with the exception of one wetland area along the west side of the creek south of SW 27'' Street. Under the current methodology, the "storage" simulation establishes the base flood elevations at the downstream portion of the system. During key periods of the "storage" event, the BRPS would have to shut down to 0 cfs for a four hour period. During the four hour period with no outlet, the system backs up and stores water. Filling in the floodplain and wetlands would eliminate storage volume to hold this ponded volume and would translate into increased water levels in the lower portion of the system. Thus, the approach to mapping the floodway for this current study had to focus on maintaining a significant majority of the floodplain, and in particular the valley wetlands, as floodway. The second reason is that the floodway in the previous FEMA study was noted to encroach upon the active channel in several locations. This is undesirable because the active channel can have fast moving flood flows and represent a hazard. Therefore, in the areas where the existing floodway encroached upon the active channel, the floodway was widened, as a minimum, to span over the active channel. Therefore, the approach to develop the new floodway was to first evaluate the prior floodway and widen it where it appeared that the prior floodway encroached upon the current active channel. These areas are noted in Table 10. Second, the floodplain and wetlands were assumed to be "filled" in an iterative fashion until the simulation caused no more than a 1-foot rise in the water surface profile for both the "storage" and "conveyance" events. As discussed above filling of the floodplain and wetlands could not be done to the extent shown in the prior study. In discussions with the City, some options for filling in the floodway/wetlands were discussed. One option would be to fill in small portions along the floodplain and/or edges of existing wetlands. The second option, which was the option selected by the City included identifying selected wetlands as floodway including those that are owned by the City and are intended to remain as wetlands. These include wetlands (I I a, 11 b and 11 (the Panther Creek wetlands) as well as wetlands 4, 6, 7a and 7b) shown on Figure 1 and depicted on Exhibit B). It was assumed that wetlands 3, 5, 7c and 12 were not in the floodway and were filled in. These wetlands were excluded from the floodway because they are privately owned and their storage volume was not required in order to keep the increase in water surface elevation from exceeding one foot. It is noted that while this method for establishing the floodway allows for future filling of the floodplain, the City, as required by the State of Washington Growth Management Act, has adopted flood hazard and wetland critical area ordinances that require replacement of compensatory storage when filling of the floodplain is proposed as well as mitigation of wetlands that are impacted. The replacement of compensatory storage requires proposed actions to recreate any floodplain storage lost from current conditions to an equivalent storage volume (i.e., floodplain storage at each elevation must be replaced with equivalent storage at that same elevation). RASeattle\l1-00781 Springbrook Creek FEMA remapping\Reports\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06R. W. Beck 4-3 Section 5 REFERENCES Customer Services Training Center (CSTC) Technical Information Report on the Floodplain/Stormwater System, Sverdrup, April 1992. East Side Green River Watershed Project Hydraulic Analysis Report Existing Drainage System, R.W. Beck, Inc, March 1996 Flood Insurance Study, King County, Washington, FEMA, November 8, 1999 Hydrologic Analysis for Floodplain Mapping Study for Springbrook Creek, King County, Washington (NHC, October 25, 2005) Revised Pump Operations Procedures Plan for the Black River Pump Station, Memorandum to Scott Woodbury (City of Renton) from Malcolm Leytham (Northwest Hydraulic Consultants), March 22, 1995 Springbrook Creek Channel and Habitat Improvement Project CAG-00-96 Technical Memorandum Hydraulic Analysis, R. W. Beck, Inc, October 2000. Springbrook Creek Channel and Habitat Improvement Project CAG-00-96 Technical Memorandum Hydraulic Analysis — Supplemental (R. W. Beck, April 2001) RASeatt1e\I1-00781 Springbrook Creek FEMA remapping\Rgwns\FEMA Final\SpringbrookHydraulicsFinal.doc 8/9/06 Exhibit A FLOOD PROFILES 35 W W W 30 —� LL U O Y O 25 Co O z O J � LL Cn 20 15 10 5 - -- ---wwww I Va/l!V i uuuu i oouu I iuuu 11500 18000 18,500 19000 19500 STREAM DISTANCE IN FEET FROM BLACK RIVER PUMP STATION U z Q w z 2 Z Q O z Z Q � W U z W LL of O W W J wU 0 w w 03P Exhibit B FLOODPLAIN AND FLOODWAY BOUNDARY MAP w Appendix A HYDROLOGIC ANALYSIS FOR FLOODPLAIN MAPPING STUDY FOR SPRINGBROOK CREEK Memorandum To: Allen Quynn and Ron Straka, City of Renton From: David M. Hartley and Derek L. Stuart, northwest hydraulic consultants, inc. Date: Revised October 25, 2005 Re: HYDROLOGIC ANALYSIS FOR FLOODPLAIN MAPPING STUDY OF SPRINGBROOK CREEK, KING COUNTY, WASHINGTON cc: Michael Giseburt, R.W. Beck Executive Summary This memorandum documents the hydrologic methods and results associated with a floodplain re -mapping study of the lower 3.1 miles of Springbrook Creek between the Black River Pump Station (BRPS) and SW 43d Street (also called South 180`h Street), which is the approximate boundary line between the Cities of Renton and Kent, Washington. The study reach is shown on FIRM numbers 53033CO976 F and 53033CO978 F revised May 16, 1995. On these maps, the BRPS is labeled "P-1 Pumping Station". Hydrologic analyses for this project were conducted following the approach described in an earlier nhc memorandum. This approach was reviewed and approved by the FEMA Map Coordination Contractor in a letter to the City of Renton, dated September 25th, 2002. Continuous hydrologic simulation modeling for a 53 year period of record (October 1, 1948 through September 30t', 2002) were used to identify and adjust storm inflow hydrographs to Springbrook Creek that correspond to recurrence intervals required for unsteady flow hydraulic modeling and subsequent floodplain mapping. Two types of potential flood generating peak events were identified for hydraulic analysis: storage events that produce very high water surface elevations at the Black River Pump Station where flood waters from Springbrook Creek are pumped to the Green River and conveyance events that exhibit maximum peak flows into the pump station forebay. Results of the frequency analysis are summarized in the following tables. Peak Inflow to Forebay for Con ve ance Limited Storm Events Current Conditions Return Period Flood Frequency Analysis' (cfs) Simulated (cfs) Multiplier2 Date of Simulated Event 2 710 707 1.00 12/3/1968 10 977 941 1.04 2/7/1955 _ 25 1100 1125 0.98 2/8/1996 50 1209 1153 1.05 1/9/1990 100 1307 1153 1.13 1/9/1990 'Flood Frequency quantiles estimated from the simulated peak flow data using Bulletin 17B procedures 2Muttiplier to scale simulated hydrograph to match estimated flood frequency quantile Storage at Forebay for Stora a Limited Storm Events, Current Conditions Return Period Estimated Stage Simulated z Date of Simulated (years) Frequency (acre-ft) Event Multiplier Event Quantiles' (acre-ft) 106 110 0.99 2/10/1951 50 243 121 1.33 12/7/1975 494 1.03 2/8/1996 100 515 'Used Gringorten plotting position to define event return period 2Multiplier to scale simulated hydrograph to match estimated flood frequency quantile As shown in the tables above, 100-year storage volumes (and water surface elevations) were nearly matched by simulation of the flood event that occurred in February, 1996, while the largest simulated peak discharge in the study reach occurred in January, 1990. The simulated peak flow for the January, 1990 event was approximately 13% less than the estimated 100-year peak flow. The unsteady flow hydraulic model will be applied to each of these 100-year conditions to estimate the base flood water surface elevations throughout the system. 2 Introduction Springbrook Creek drains a basin of approximately twenty five square miles located in a highly urbanized area of western King County, Washington (see Figure 1). The basin is bounded on the west by the Green River levee system and on the east by uplands of the Soos Creek basin. The creek drains portions of the cities of Kent, Renton, Tukwila, and unincorporated King County; however, Kent to the south and Renton to the north are by far the largest areas within the basin. The predominant drainage direction of the basin is from south to north along the mainstems of Springbrook Creek and its major tributary, Mill Creek, which drains the southwestern portion of the East Side Green River Watershed. The east side of the basin consists of an upland plateau which is drained by creeks in steep ravines. These include Rolling Hills Creek, Panther Creek, Upper Springbrook Creek, and Garrison Creek, which all drain to the mainstem of Springbrook Creek. Upper Mill Creek drains the southeastern, upland headwaters of the Mill Creek tributary into Middle Mill Creek on the valley floor near downtown Kent, WA. Besides the major creek branches and upland tributaries, significant hydrographic features in the basin include Panther Lake in the headwaters of Panther Creek subbasin, the Panther Creek wetland along the northeastern margin of the valley floor, and the Kent Lagoons within the Green River Natural Resource Area in the southwestern corner of the basin. Currently, during moderate and large floods on Mill Creek, water is diverted to the lagoons for storage and later release (see Figure 1). The eastern, upland sub -basins and their associated ravines comprise approximately 40% of the basin area. The flat, western, lowland valley areas (Springbrook Creek subbasin, Middle Mill Creek subbasin, and Lower Mill Creek sub -basin) make up the remaining 60% of the basin. Surficial geology of the upland areas tends to be dominated by relatively low permeability glacial tills, while the valley is dominated by wetland soils and highly variable Green River alluvium. Landuse in the upland areas is primarily single family suburban residences with scattered parks and commercial areas, while valley areas tend to be dominated by commercial and industrial uses with some high density multifamily residential development and recreational areas. This technical memorandum documents the hydrologic analysis conducted for purposes of revising the Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM) of Springbrook Creek from the Black River Pump Station (BRPS) upstream to SW 43'd Street, Renton, Washington. This analysis has been conducted in accordance with the methodology described in a technical memorandum dated July 25, 2002, prepared by Northwest Hydraulic Consultants for the City of Renton. For technical review, the 2002 memo was forwarded by the City to the FEMA Map Coordination Contractor who found that "the approach and methodology is reasonable and appropriate for floodplain mapping purposes". (Andrea Ryon, Michael Baker, Jr., September 25, 2002). Unsteady flow (hydrodynamic) hydraulic modeling will be used to characterize water surface profiles in Springbrook Creek in order to account for dynamic flood storage in basin wetlands and, more significantly, to accurately simulate flood discharges from Springbrook Creek to the Green River, via the Black River Pump Station (BRPS). Pump station operations, including limitations on pumped discharges when Green River flows are high, impose a dynamic downstream boundary condition on the Springbrook Creek drainage system. 3 Hydrologic Model Development Stream flow data has been collected by the USGS since 1994 on both Mill Creek (gage 12113349) and Springbrook Creek (gage 12113346), upstream of their confluence. Additional flow data has also been collected by King County and the cities of Renton and Kent at other locations within the basin. While these data are useful for purposes of calibrating or validating a hydrologic model, they are insufficient in record length or homogeneity to provide a database of annual peaks for flood frequency analysis. Likewise, the application of regional regression equations to determine peak annual flow frequency curves was determined to be inapplicable in a highly urbanized, hydraulically dynamic, and complex basin such as Springbrook Creek. Based on the available data and basin conditions, the Hydrologic Simulation Program Fortran (HSPF) model was selected as the primary tool to generate flood hydrographs for input into a Full Equations Model (FEQ), which will be used to estimate water surface elevations corresponding to events of specified recurrence interval in the study reach. A continuous, hourly precipitation record from Seattle -Tacoma International Airport (NWS gage 7473 at Sea-Tac), spanning water years 1949-2001, was used to generate 53 years of continuous flows at points of interest within the study reach and at boundary inflow points to the FEQ model. A schematic of the FEQ model, showing locations where HSPF-generated hydrographs are input as boundary conditions, is provided in Figure 2. Note that the FEQ model only covers the study reach which is located in the northern half of the Springbrook mainstem subbasin, shown in Figure 1, downstream of the confluence of Mill Creek with Springbrook Creek. 3.1 Development of the Basin Hydrologic Model The HSPF model of the Spingbrook basin consists of a set of hydrologic response units (HRUs) representing pervious and impervious land surfaces that drain to elements of the routing network, including stream reaches, lakes, stormwater facilities, and other features of the drainage system. Hydrologic response units and their spatial distribution within each subbasin were determined using methods described below. 3.1.1 Subbasin Delineation Basin boundaries and subbasin delineations in the upland portion of the basin were delineated using the best available topography data (City of Kent, 5ft; City of Renton, 0.5 meter) and King County GIS stream data, corrected using recent digital orthophotos (City of Renton 1999; USGS, 1990). Subbasin delineations in the lowland regions were based on previous drainage studies conducted for the cities of Renton and Kent (nhc, 1996 and 1994, Gray and Osborne, 2003). (A detailed HSPF catchment map is provided in Figure 3.) 3.1.2 Surficial Geology Basin soils were classified as till, outwash, wetland, or alluvium. The spatial distribution of basin soils was determined from the King County surficial geology GIS coverage which was converted to a basin -wide GIS layer of the four soil classes- till, outwash, saturated, and alluvium (see Table 1). Till and outwash dominate the upland plateau and ravine areas, while alluvium dominates the flatter, floodplain shared by Springbrook Creek and the Green River. (A surficial geology map is shown in Figure 4.) Table 1: Cross -Reference of Soil Classification and GIS Soil Type Soil Classification GIS Soil Type Alluvium Modified land (Holocene) Alluvium Younger alluvium (Holocene) Outwash Advance outwash deposits Outwash Recessional outwash deposits Outwash Recessional outwash deposits lowland lacustrine Till Mass wastage deposits Holocene and Pleistocene Till Sedimentary deposits of re -Fraser glaciation age Till Transitional beds (Pleistocene) Till Surficial deposits, undivided Holocene and Pleist Till Ice contact de osits Till Till Till Vashon Drift, undivided Till Intrusive Rock (Miocene, Oligocene & Eocene) Till _ Renton Formation (late and middle Eocene) Till Tukwila Formation late and middle Eocene Water water Wetland Wetland deposits (Holocene) 4 3.1.3 Current Land Cover Homogeneous land cover polygons were delineated by hand on hardcopies of orthophotos provided by the City of Kent (July, 1999), City of Renton (1999), and King County (June 16, 2000). These were merged with wetland GIS data provided by the City of Kent, City of Renton, and King County. Delineated land cover classes included commercial, multifamily, high density residential, medium density residential, low density residential, grass, forest, and wetland. Multifamily areas are defined by attached housing with greater than seven dwelling units per acre, high density areas have four to seven dwelling units per acre, medium density have one to three dwelling units per acre, and low density have less than one dwelling unit per acres. The land cover polygons were digitized into a basin - wide coverage of land use. (Current land cover is shown in Figure 5.) 3.1.4 Wetlands A basin -wide wetlands GIS coverage was created from available data from King County and the cities of Kent and Renton. The coverage represents designated wetland land use areas that are assumed to remain undeveloped in the future. These are distinct from the broader coverage of saturated, wetland -type soils. (Designated wetlands are also shown on Figure 5.) 3.1.5 Determination of Subbasin HRU Acreages GIS processing of subbasin, soils, and land cover layers was used to create subbasin summaries of land cover -soil complexes. The land cover component of these complexes was further processed to create impervious and pervious HRU acreages for each modeled subbasin using conversions shown in Table 2. These conversions represent typical values applied to these land use categories for HSPF modeling in the Lower Puget Sound region. Table 2: Derivation of Modeled Land Cover from Mapped Land Categories GIS Mapped Land Cover Category Modeled Land Cover Category Percentages Effective Impervious Grass Forest Wetland Commercial Forest Grass -Open High -Density -Residential 86 0 5 25 14 0 0 0 100 0 80 15 0 70 5 0 Open -Water' 0 0 1 0 100 Low -Density -Residential 5 75 20 0 Medium -Density -Residential 15 70 15 0 Multi -Family -Residential 45 50 5 0 Wetlan& 0 0 0 100 Open water areas were modeled as wetland HRUs with the exception of Panther Lake which was modeled as a routing reach (RCHRES) that receives rainfall loses water to evaporation from its surface. Wetland areas represent the union of wetland or "saturated" soil areas that are not currently covered by impervious surfaces and legally protected and designated wetland land use areas. The resultant combinations of soil and cover make up an inventory of acreages for each subbasin in which all land is categorized as one of eight HRUs. These units are: 1. Effective Impervious Area (EIA) 2. Till Forest (TF) 3. Till Grass (TG) 4. Outwash Forest (OF) 5. Outwash Grass (OG) 6. Wetland (W) 7. Alluvium Forest (AF) 8. Alluvium Grass (AG) A summary of the acreages of each HRU by major subbasin is provided in Table 3. Basin -wide, over 42% of the basin is EIA or impervious area that is directly connected to the drainage system. Impervious area is heavily concentrated in the commercial and industrial areas of the flat Green River valley within the Springbrook, Middle, and Lower Mill Creek subbasins. HRU acreages for individual catchments within the major subbasins are shown in the schematic block of the HSPF input files in the digital appendix. Table 3: Summary of HRU Acreages by Major Subbasin- Current Land Use Subbasin EIA TIT TG OF OG W AF AG Water Total Area (ac) (ac) (ac) (ac) (ac) (ac) (ac) (ac) (ac) (ac) Springbrook 2152 296 437 1 1 3 487 1 153 703 4232.5 Rolling Hills 293 90 507 0 8 1 2 24 925.7 Panther 372 1 294 835 1 1 156 4 4 33 1 1700.2 Upper S rin brook 86 123 250 51 12 48 3 0 573.8 Garrison 539 383 1294 0 0 118 2 2 2338.2 Lower Mill 0 0 0 0 361 83 838 3481.8 Middle Mill r756 16 93 0 0 53 19 248 1184.9 Upper Mill431 237 761 0 0 90 8 5 1531.8 Basin Sum 6795 1439 4176 53 24 1315 8.2% 274 1826 33 15968.5 Basin % 42 9% 9.0% 26.2% 0.3% 0.1% 1.7% 11.5% 0.2% 100.0% 6 3.2 Development of Routing Network Model Components HSPF routes runoff in the drainage network using a level -pool routing method in which each routing reach is represented with a unique elevation -storage -discharge table known as an FTABLE. Figure 6 provides a schematic of the HSPF catchments and routing network. Each circle represents a catchment and each arrowed line represents a reach that requires a corresponding FTABLE within the model. Routing network topology and FTABLES used in the HSPF model were based primarily on previous hydrologic and hydraulic modeling work conducted for the cities of Renton and Kent. (nhc, 1996, R. W. Beck, 1996). The network and FTABLES from these earlier models were updated to include alterations and improvements to the system installed since the mid-1990s using as - built drawings, reports, and field observations. HEC-RAS modeling of the mainstem of Springbrook and Mill Creeks was utilized to estimate HSPF FTABLES for these low gradient streams. The routing portions of the HSPF model were updated to include the following recent alterations of the drainage system: 1. New bridges, channel improvements, and culvert upgrades along Springbrook Creek between SW 16th Street and SW 41St Street were incorporated into the HEC-RAS model used to generate Springbrook Creek FTABLES (Reaches 13, 15, 21, and 27 on Figure 6). 2. A new outlet for Panther Creek wetland crossing under SR 167 and connecting to a tributary of Springbrook along SW 23rd Street was added (Reach 101 on Figure 6) to the routing network. 3. A new culvert connecting Subbasin 9 in the City of Tukwila to Springbrook Creek at SW 16th Street was added to the model. 4. Regional stormwater facilities including the Green River Natural Resource Enhancement Area (Kent Lagoons) in lower Mill Creek (Reach 65), and the 98th Avenue detention pond on the southernmost ("Benson") fork of Garrison Creek (Reaches 325, 325, 327). 5. Improved Upper Springbrook Creek culvert crossing at SR 167 (Reach 203). 3.2.1 Model Calibration The HSPF model was calibrated to streamflow data from water years 1995 and 1996 using land use, channel, and basin storage conditions representative of that time period. Gage records used for calibration included USGS data from gages upstream of the study area (HSPF reaches 33 and 51) and from the gage maintained by Northwest Hydraulic Consultants for the City of Renton at SW 27th Street within the study area (HSPF reach 21). Storms were relatively large and numerous during the calibration period and included the peak of record at the USGS gage sites making this a very good period for calibrating to flood conditions. The downstream gage record was employed as the primary gage for checking model performance because of its location within the study reach. 3.2.2 Parameter Values and Model Calibration The USGS (Dinicola, 1989) studied the application of HSPF to stream basins in the Puget lowland and developed a set of parameter values for the most common HRUs found in this region. Since the publication of that study, the USGS regional parameter values have become the starting point for most HSPF model calibration studies. Within the Springbrook basin model, a subset of the standard USGS HRUs have been employed and augmented by two additional HRUs representing grass -alluvium and forest -alluvium as reflected in Table 3. Pervious areas in the Sprinbrook valley subbasins are dominated by alluvium as compared upland subbasins in which till and outwash soils prevail. Calibrated HSPF parameter values for all HRUs are summarized in Table 4. In upland subbasins dominated by till and outwash soil HRUs, with the single exception of DEEPFR, there are no significant differences between the final calibration parameters and the regional parameters developed by the USGS. The DEEPFR parameter removes a fraction of groundwater from the surface drainage system of a basin to account for losses to inactive groundwater (or a regional groundwater system). This parameter was set at 0.45 for all HRUs and signifies that simulated annual and seasonal volumes of stream flow best matched observed volumes when 45% of base flow was assumed to be lost from the stream system. This is not unreasonable within the Springbrook basin given that the coarse valley alluvium provides ample opportunity for groundwater to escape to either the Green River or deep percolation. In any case, peak flood discharges are not generally sensitive to DEEPFR values and are even less so in this heavily urbanized basin. Table 4. Calibrated HSPF Parameter Values Parameter Units HRU(HSPF IMPLND and PERLND H)s) EIA 11) TF (13) TG (23) OF (31) OG (41) W (51) AF (62) AG (72) FOREST - N/A 0.75 0.05 0.75 0.05 0.75 0.75 0.05 LZSN IN N/A 4.5 4.5 5.0 5.0 4.0 2.0 2.0 INFILT IN/HR N/A 0.08 0.03 2.00 0.80 2.00 1.001 0.40 LSUR FT N/A 400 400 400 400 100 400 400 SLSUR - 0.01 1 0.10 0.10 0.05 0.05 0.001 0.01 0.01 KVARY _ IN N/A 0.50 0.50 0.30 0.30 0.50 0.05 0.05 AGWRC DAY N/A 0.996 0.996 0.993 0.993 0.996 0.998 0.998 INFEXP - N/A 2.0 2.0 2.0 2.0 10.0 2.5 2.5 INFILD - N/A 2.0 2.0 2.0 2.0 2.0 2.0 2.0 DEEPFR - N/A 1 0.45 0.45 0.45 0.45 0.45 0.45 0.45 BASETP - N/A 0.0 0.0 0.0 0.0 0.0 0.0 0.0 AGWETP - N/A 0.0 0.0 0.0 0.0 0.7 0.0 0.0 CEPSC IN N/A 0.20 0.10 0.20 0.10 0.10 0.10 0.10 UZSN IN N/A 1.00 0.50 1.00 0.50 3.00 0.25 0.50 NSUR - 0.10 1 0.35 0.25 0.35 0.25 0.50 0.25 0.50 INTFW - N/A 6.00 6.00 0.00 0.00 1.00 5.00 5.00 IRC DAY' N/A 0.35 0.35 0.70 0.70 0.70 0.60 0.60 LZETP - N/A 0.70 0.25 0.70 0.25 1 0.70 0.80 0.80 RETSC IN 0.10 N/IA N/A N/A N/A NIA N/A N/A The lowland, valley subbasins are dominated by commercial and industrial development with high rates of hydraulically connected (effective) impervious area (EIA). The Springbrook subbasin, and the Middle and Lower Mill Creek subbasins, are currently more than 50% covered by EIA. There are only a few EIA parameters and typically they are not adjusted in an HSPF calibration. Grass on alluvial soils dominates the pervious areas of these subbasins. This HRU was initially assigned parameter values that were enerally a hybrid till and outwash soil parameter values. During calibration, alluvium HRU parameters were adjusted by comparing simulated and observed flows at the Mill Creek USGS gage. In general, trial runs of the model produced flashier response with higher peak flows compared to the observed flows at this gage. Even so, only limited improvement in overall model performance could be achieved by adjusting these parameters because flood response of the model was so strongly dominated by the high rate of impervious area in valley. 3.2.3 Valley Storage Added to Model Given the overly flashy response of the model and the relative insensitivity of simulated flows at the Mill Creek USGS gage site to PERLND HRU parameter changes, it was reasoned that the model was under -representing the dispersed hydrologic storage within the many flat parking lots and ditches that exist in the valley areas. Although much of the Mill Creek basin between Earthworks Park (Reach 401) and the confluence with Springbrook Creek (Reach 51) consists of commercial development with a very high percentage of total impervious area, this portion of the basin lies within the relatively flat -gradient Green River valley where there are many opportunities for impervious surface runoff to pond prior to entering the main stem of Mill Creek. To achieve a reasonable calibration on Mill Creek, storage that is approximately equivalent to the City of Kent stormwater standard for the valley was assumed to be in place for a portion of existing impervious area. This standard is equivalent to approximately 3.0 inches of depth over the contributing impervious area. Outflow from the storage was based on an overflow of approximately 0.9 cfs per ac-ft of storage or 0.23 cfs per acre of contributing impervious. Trial runs of the model and comparisons with observed storm hydrographs were then used to adjust the portion of impervious area subjected to the assumed storage. This resulted in storage being applied to 52% of the impervious area runoff within each of eleven subbasins (53, 57, 61, 63, 65, 67, 81, 85, 87, 91, 93 ). A similar amount of storage was also added to other valley areas within the City of Kent to represent stormwater mitigation that was required by the City for impervious areas constructed after 1996. One exception to this assumption was made for post-1996 development in the areas draining directly to Green River Natural Resource Area (GRNRA). No on -detention storage was added for recent development in these areas as all development in this basin is directed to the regional storage in the GRNRA as part of the LID that created this project. 9 3.2.4 Peak Flow Table 5 shows the results of the calibration in terms of instantaneous storm peak discharges and storm volumes for the nine largest storm events of the two year calibration period. At the SW 27`h Street gage site, modeled hourly storm peak discharges differed from gaged peak discharges by between -16% and 42%. The RMS of the error percentages is 17% and average model bias is very low (approximately +1 %). Model error for the peak of record (rank = 1) on February 9, 1996 is 2%. The largest peak error (42%) occurs on November 11, 1995, one of the smallest storm peaks (rank =8). Based on these results, the model is considered to be well calibrated for prediction of peak discharges within the study reach. Similar agreement was obtained between simulated and observed peaks at the USGS site on Springbrook Creek, but simulated flows at the USGS site on Mill Creek (gage 12113349) tended to consistently overestimate the gaged peaks. The USGS rates the Mill Creek gage record "poor" for the larger peak discharges (> 200 cfs), and "fair" otherwise. The Springbrook gage record was rated "poor". Given the relatively low reliability of these gages and their location upstream of the study reach, model performance in matching flow records is not considered as significant as at the SW 27th Street gage site. 3.2.5 Storm Volumes The range of errors for storm volumes at the SW 27`h Street gage is -23% to 20% with an RMS error 17% and an average bias of -12%. The bias suggests that the model moderately underestimates storm volumes at this site. In contrast, results at the other two gages suggest an over estimation of 17% on the Springbrook branch and 12% on the Mill Creek branch. Based on drainage area, the sum of storm volumes at the upstream gages should equal 92% of the storm volume at the SW 27`h gage. Clearly, the three gage records are not consistent with one another. The USGS gages consistently (8 out of 9 storm events) predict less volume by an average of 2 1 % than is indicated by 92% of the recorded volume at SW 27`h Street. Given the previously mentioned issues with data quality at the USGS gages and the inconsistency of recorded volumes among the gages, there was no basis on which to make further adjustments to the HSPF model and the calibration was judged to be adequate within the study reach. In addition to storm peaks and volumes, model agreement with gaged data was checked for annual and seasonal flow volumes. Results of these checks are considered to be of minor importance to the floodplain study, but they are provided in Appendix A for reference purposes. 10 Table 5: Simulated and observed instantaneous storm peak discharges and storm volumes for nine largest storm events during water years 1995 and 1996 Peak Date Peak Rank Springbrook Creek near Orillia USGS 12113346 Mill Creek near Orillia USGS 12113349 Springbrook Creek at SW 27th Renton OBS SIM ERROR OBS SIM ERROR OBS SIM ERROR 11/30/1994_1 6 1 Storm Vol ac-ft) 6919 8595 24% 11202 12943 16% 26958 23356 -13% Peak cfs 129 123 -5% 145 169 17% 353 318 -10% 12/20/1994 7 Storm Vol ac-ft) 11459 15616 36% 21486 23699 10% 19% 52856 328 42638 318 -19% -3% Peak (cfs) 117 125 7% 151 179 �_... 12/27/1994 __ 5 Storm Vol (ac-ft) ....._ 7660 11097 .. 45°i� 13682 15832 16% 32573 28918 -11% Peak cfs 1 43 171 20% 187 221 18% 357 _ .._........__._ 399 12% 2/18/1995 3 Storm Vol (ac-ft) 11757 20574 75% 22489 28447 26% 57650 52737 -9% Peak cfs) 148 184 24°/> 189 250~ 32% 472 441 -6% 11/11/1995 8 Storm Vol ac-ft) 84-' 7824 -7% 8992 11778 31% 17666 ..�..... 252 21220 _.,. 358 ..,_ .... 20% 42% Peak cfs _._m......... 191 153 -20% 131 __.._. 222 _ 70%... 11/29/1995 4 Storm Vol (ac-ft 25944 19186 -26% 25752 28071 9% 62093 099 50997 -18% _.-- - ---. - Peak (cfs) 202 147 -27% 162 198 23% 364 350 _ - -4% 1/21/1996 9 Storm Vol ac-ft 24294 23654 -3% 35887 34533 -4% 81244 62870 -23% Peak cfs 89 71 -20% 86 105 23% 218 192 -12% 2/9/1996 1 Storm Vol ac-ft) 36395 33033 -9% 45093 43145 -4% 96359 82401 -14% Peak cfs 447 347 -22% 376 423 13% 714 731 2% 4/24/1996 2 Storm Vol ac-ft 11890 15441 179 30% 3% 18183 20222 11% 46537 38358 -18% Peak (cfs 175 189 238 26% 498 419 -16% 11 4 Hydrologic Simulation and Analysis Methods The calibrated HSPF model was applied to the task of identifying and generating design storm hydrographs for input into the FEQ hydraulic model for subsequent unsteady flow hydraulic analysis. The approach used was summarized by nhc (2002) in a previous technical memorandum and duly reviewed and accepted by FEMA's Map Coordination Contractor (Personal Communication, Andrea Ryon, 2002). Methods applied in this study are described in detail in the memo and in the East Side Green River Watershed Hydrologic Analysis Report (nhc, 1996) and will not be repeated here with the exception of a summary of updates and improvements applied to the data and analysis as listed below. 4.1 Updates and Improvements to Analysis Land Use/Cover- the previous study (nhc, 1996) applied land use from the late 1980s. Land use and cover in the hydrologic model was updated as previously described in this memo. 2. Hydraulics- routing reaches were updated to reflect modifications to basin channels and storage facilities as described above in this memo. 3. Precipitation Data and Simulation Time Span- the previous study applied the hourly precipitation record from the NWS gage 7473 at SeaTac Airport from October 1, 1962 through September 30, 1991 (29 water years) to simulate flows within the basin for the same time period. The current study applied a longer precipitation record to simulate flows spanning 53 water years from October, 1949 through September, 2001. Lengthening of flood records generally improves the estimate of flood frequency curves, especially when the additional record includes the peak flood of record in the basin which took place in February, 1996. 4. Backward Extension of the Green River Record of Control Flows- In order to extend the hydrologic analysis by taking advantage of the full NWS precipitation record, Green river flows at Auburn resulting from flood operations of Howard Hanson dam had to be synthesized for the period spanning water years 1949 through 1962 because the dam had not been completed and did not control Green River flows during this time. Recall that flow measurements at Auburn are used to guide operations of the Black River Pump Station (BRPS) at the mouth of Springbrook Creek such that when the Green River flows are higher than 10,500 cfs, BRPS pumping becomes progressively more constrained. Based on guidelines provided by the Seattle District Corps of Engineers (Personal Communication, Marian Valentine, 2003), the following rules were applied to the synthesis of controlled flows at Auburn: a. The historically recorded Auburn hydrograph is used to estimate the rising limb of the controlled flood between the base flow level and 10,000 cfs. 12 b. When recorded floods reaches 10,000 cfs, it is assumed that control of the flood maintains that level until the time of the peak of the uncontrolled hydrograph. c. Once the peak has occurred, the flow rises over a 10 hour period to a level just below 12,000 cfs. The 10 hour transition period to the higher level reflects time lag between the dam and Auburn (8 hours) and operational decision making time (2 hours). For purposes of modeling BRPS operations, this level will be taken as 11,750 cfs- a level-2 constraint allowing a maximum BRPS output of 400 cfs. The next highest constraint level would be zero BRPS discharge. The near-12000 cfs level will be maintained long enough to evacuate stored water and provide an acceptable ramp -down rate. The ramp -down rate recommend by the COE is the rate that was operative during the February, 1996 flood event (approximately 1600 cfs per day). These guidelines were used to identify floods that would cause constrained pumping conditions at the BRPS. Daily mean flow records were used to screen flood events during the 1949-1962 period for events that could possibly constrain BRPS operations. Three candidate events, taking place in February of 1951, December of 1955, and November of 1959, were identified and paper charts for these events were obtained from USGS archives and digitized to produce an hourly record of historical flows. As it turned out, only the February, 1951 and November, 1959 caused any significant constraint on BRPS pumping. Figures showing the historical and synthesized hourly flows for these two events are shown in Appendix B . All other hourly discharges during the 1949-1962 period were assumed to equal the recorded mean daily discharge. 4.2 Identification of Design Events for FEQ Modeling The HSPF model of the Springbrook basin was executed for the period of record to develop two types of design events for FEQ modeling: conveyance events and storage events. It should be noted that the same model run was used to identify both types of events. The difference between the two types of events is that the conveyance events are based on frequency analysis of peak annual discharges at the entrance to the BRPS forebay, and the storage events are based on a frequency analysis of peak annual forebay storages. Both the discharges and storages result from the same combined run of HSPF and the BRPS model. These two sets of events will be modeled separately in FEQ to determine two water surface profiles for each recurrence interval modeled. The maximum of these two water surfaces elevations will be used for floodplain mapping throughout the study reach. 4.2.1 Conveyance Events Conveyance events were identified by running the model for 53 years of record, extracting the simulated annual peaks for the total discharge of the Springbrook drainage system at the BRPS forebay (Reach 1, Figure 6), and fitting the standard Log -Pearson III frequency curves using the HEC-FFA program with regional skew set to 0.0. Full results of the HEC-FFA run are shown in the digital appendix in the file BRPSCUR.PDF. Figure 7 shows the fit of the simulated peak annual flows to the Log -Pearson III frequency curve fitted by HEC-FFA. Using the HEC-FFA output, specific floods from the simulation 13 record were selected that most closely approximated the Log -Pearson III quantiles and hydrograph correction factors were estimated based on the ratio of the quantiles to the simulated peaks. A summary of simulated peaks, quantiles, and multipliers is provided in Table 6. HSPF simulated hydrographs for these storm events, corrected by the multiplier, were then used as boundary conditions representing events of specified recurrence in the FEQ hydraulic model of the study area. Table 6: Peak Inflow to Forebay for Conveyance Limited Storm Events, Current Conditions Return Period Flood Frequency Analysis' (cfs) Simulated (cfs) Multiplier Date of Simulated Event 2 710 707 1.00 12/3/1968 10 977 941 1.04 2/7/1955 ^� 25 1100 1125 0.98 2/8/1996 50 1209 1153 1.05 1/9/1990 100 1307 1153 1.13 1/9/1990 'Flood Frequency quantiles estimated from the simulated peak flow data using Bulletin 17B procedures ZMultiplier to scale simulated hydrograph to match estimated flood frequency quantile 4.2.2 Storage Events Storage frequency analysis was undertaken for the BRPS forebay to identify storm events that produced the largest amount of storage and associated backwatering of lower Springbrook Creek. To perform the storage frequency analysis a special routing model, BRPS-SIM, was employed to represent BRPS operations with due consideration to constraints on pumping as mandated in the Green River Pump Operations Procedure Plan (POPP) (King County, 1986) and dictated by high Green River flows as measured at the USGS gage at Auburn. Because the pump station is operated by a set of deterministic rules, forebay storage does not follow any particular probability distribution. Therefore, the peak annual storage data extracted from the BRPS-SIM model were plotted using a Gringorten plotting position and a least squares curve was fit through the four largest peaks as shown in Figure 8. This figure was then used to identify storm events that most closely resembled 25-, 50-, and 100-year quantiles. Trial and error was then used to determine appropriate hydrograph multipliers that would produce the desired storage quantile, using a storm event from the simulated record. As shown in Table 7, 25-year and 100-year storages were very closely approximated by the February, 1951 and February, 1996 events. The 50-year storage can be approximated by the December, 1975 event; however, the inflow hydrograph discharges must be increased by 33% to produce the desired storage level in the pump station forebay. Table 7: Storage at Forebay for Storage Limited Storm Events, Current Conditions Return Period Estimated Stage Simulated Event Date of (years) l (acre-ft) Multiplier2 Simulated Event QuaFrequency (acre-ft) 25 106 110 0.99 50 243 _ 121 1.33 "26 100 515 494 1.03 Used Gringorten plotting position to define event return period ZMultiplier to scale simulated hydrograph to match estimated flood frequency quantile 14 4.3 Data Transfer to FEQ Model The FEQ model (Figure 2) requires inflow hydrographs at 22 locations. For each of these locations, the entire 53-year record of hourly flows simulated by the HSPF model was stored in a WDM database for subsequent processing and input to the FEQ hydraulic model. The identified conveyance and storage storm events described above were used to select simulation periods for FEQ modeling. Corresponding storm event multipliers, as described above, were applied to database flow values for the selected time periods to create the inflow hydrographs used in all FEQ model runs. 5 Comparison of Results with Effective FIS Results of this hydrologic analysis were compared with the effective FIS (FEMA, 1999). Estimated flood quantiles from the conveyance event flood frequency analysis were compared to the past study as shown in Table 8. Table 8: Comparison of Current Study with Effective FIS Inflow to Black River ("P-1") Pump Station Study 10-year 50-year 100-year 500-year' (cfs) (cfs) (cfs) (cfs) Effective FIS 650 1040 1230 1730 (FEMA, 1999) 978 Current Study 1210 1310 (nhc, 2003) 50% N/A %change 160o 7% 'Analysis of the 500-year flood is outside the scope of the current study. As shown in Table 8, flood quantiles at the BRPS forebay are much higher for more frequent events in the current study than in the effective FIS. This increase in quantiles would be expected based on the substantial increase in the intensity of land development in the basin since 1980 when the hydrology study employing the effective FIS was first reported. Additionally, that study employed a design storm and event -based hydrology model (TR-20) rather than a calibrated, continuous model. Coincidentally, 100-year peak flows in the current study and the effective FIS are quite similar in spite of substantial changes in basin land use since the earlier study was completed. In conclusion, the results of the current hydrologic analysis are certainly more up to date and accurate than the effective FIS because they are based on a model that is calibrated with stream flow records that were not available at the time of the earlier study. 6 Summary and Conclusions A calibrated, continuous hydrologic simulation model (HSPF) was used to identify "conveyance" and "storage" flood events along lower Springbrook Creek in the City of Renton, Washington. Fifty three years of continuously simulated flows at the entrance to the Black River Pump Station provided a database from which peak annual flows were 15 extracted and used to fit a Log -Pearson III frequency curve using standard methods. The frequency curve was then used to identify hydrographs in the 53 year record that approximate the flood quantiles indicated by the curve. Correction factors for these events were determined from comparison of quantiles to simulated peaks. The correction factors were then applied to HSPF-simulated storm hydrographs at boundary locations associated with an FEQ hydraulic model of the study area. The FEQ model will be employed to determine maximum water surface elevations associated the corrected storm hydrographs and their specified recurrence intervals. A similar approach was employed to identify and adjust hydrographs for peak storage events at the BRPS forebay that could potentially maximize water surface elevations in lower Springbrook Creek. Peak storage volumes were simulated with the BRPS-SIM model using the 53 year HSPF record of forebay inflows, pump station rules, and an extended 53 year record of Green River flows. Simulated peak annual forebay storages were used to fit a non -parametric frequency curve. Similar to the method used to develop conveyance event hydrographs, the peak storage frequency curve was used to identify and adjust flood hydrographs to achieve storage volumes corresponding to the desired recurrence interval. Both storage and conveyance events of specified recurrence interval will be input to the FEQ model to determine which type causes the maximum water surface elevation at different locations within the study area. 16 References Dinicola, R. S. 1989. Characterization and Simulation of Rainfall -Runoff Relations for Headwater Basins in Western King and Snohomish Counties, Washington. USGS Water Resources Investigations Report 89-4052, 52 p. Federal Emergency Management Agency. 1980. Flood Insurance Study, City of Renton, Washington. Federal Emergency Management Agency. 1999. Flood Insurance Study, King County Washington, Volume 1, 177 p. Green River Basin Program. 1986. Final Green River Pump Operations Procedures Plan, 13 p. plus appendices. Green River Basin Program. 1992. Interlocal Agreement (Update of the Green River Management Agreement), 11 p. plus attachments. Northwest Hydraulic Consultants, Inc. 1996. East Side Green River Watershed Hydrologic Analysis, 51 p. plus appendices. Northwest Hydraulic Consultants, Inc. 2002. Proposed Methodology For Hydrologic and Hydraulic Analysis Of Lower Springbrook Creek Pursuant to 2002 Floodplain Ro-Mapping. Memorandum dated July 12, 2002 from David Hartley and Larry Karpack of Northwest Hydraulic Consultants to Ron Straka and Allen Quynn of the City of Renton. Ryon, Andrea. 2002. Personal Communication. Letter dated September 25, 2002 to Allen Quynn of the City of Renton from Andrea Ryon, Director, Engineering Division, Michael Baker Jr., Inc. R.W. Beck with Linsely Kraeger Associates, Ltd. 1996. East Side Green River Watershed Project, Hydraulic Anaaysis Report, Existing Drainage System. For City of Renton, Washington. Valentine, Marian. 2003. Personal Communication. Email of March 13, 2003 from Marian Valentine, Senior Water Manager, USA-COE, Seattle District to David Hartley of Northwest Hydraulic Engineers. 17 7 Appendix A: Supplemental Calibration Information In addition to storm peak and volume, modeled and recorded mean annual flow were compared over the water year 1995-1996 calibration period. Results of these comparisons are shown in Table Al. The modeled mean annual flow at the SW 27�' gage tended to underestimate the gaged mean annual flow by an average of 12% over the two year period. At the Mill Creek USGS gage site, the model was unbiased with respect to the mean flow over the two year period, moderately overestimating in 1995 and moderately underestimating the recorded flow in 1996. At the Springbrook USGS gage site, the model slightly overestimated mean flow in the first year and moderately overestimated mean flow in the second year. Table Al: Mean Annual Flow Com arison Springbrook Creek Mill Creek Springbrook Creek near Orillia near Orillia at SW 27' USGS 12113346 USGS 12113349 Renton GAGE SIM ERROR GAGE SIM ERROR GAGE SIM ERROR cfs) (cfs) (cfs) (cfs) (cfs) (cfs) 1995 7.5 7.8 3% 11.7 12.6 8% 26.9 22.3 -17% 1996 13.8 11.3 -18% 18.5 17.6 -5% 34.4 31.6 -8% Both Years 10.6 1 9.5 -10% 1 15.0 1 15.0 1 0% 30.5 1 26.9 1 -12% Tables A2, A3, A4, and A5 show model performance in terms of seasonal mean discharge for the two year calibration period. Overall, the match between seasonal simulated and recorded mean flows is only fair. At SW 27t', model performance in fall and winter generally tracks overall annual performance. Performance during spring and summer appears to be much more erratic. This may be a function of the quality of the stream gage record at SW 27a', where emphasis in operation and maintenance of the gage was placed on accuracy during floods more than on small base flow conditions. The agreement between the simulated and gaged flows is inconsistent and ranges from fair to poor. It appears that summer base flows are generally underestimated on Springbrook Creek and overestimated on Mill Creek. Table A2: Fall Mean Flow Comparison Springbrook Creek Mill Creek Springbrook Creek near Orillia near Orillia at SW 27`h USGS 12113346 USGS 12113349 Renton GAGE SIM ERROR GAGE SIM ERROR GAGE SIM ERROR (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) 1995 11.7 12.6 8% 18.4 21.1 15% 42.6 36.1 -15% 1996 22.3 15.8 -29% 25.2 25.6 2% 53.0 42.4 -20 /o 0 Both Years 17.0 1 14.2 -16% 1 21.8 1 23.4 1 7% 47.8 1 39.3 1 -18% 18 Table A3: Winter Mean Flow Comparison Springbrook Creek Mill Creek Springbrook Creek near Orillia near Orillia at SW 271h USGS 12113346 USGS 12113349 Renton GAGE SIM GAGE SIM GAGE SIM (cfs) (cfs) ERROR (cfs) (cfs) ERROR (cfs) (cfs) ERROR 1995 11.1 14.5 30% 20.3 21.3 5% 44.0 39.2 -11% 1996 22.1 21.3 -4% 38.0 30.9 -19% 61.7 56.7 -8% Both Years 16.6 17.9 8% 29.1 1 26.1 -10% 52.8 47.9 -9% Table A4: Sp no Mean Flow Comparison Springbrook Creek Mill Creek Springbrook Creek near Orillia near Orillia at SW 27rn USGS 12113346 USGS 12113349 Renton GAGE SIM GAGE SIM GAGE SIM (cfs) (cfs) ERROR I (cfs) (cfs) ERROR (cfs) (cfs) ERROR 1995 4.2 2.9 -32% 5.4 4.9 -10% 6.6 8.7 32% 1996 1 8.7 8.4 -3% 14.5 12.9 -11% 21.5 23.4 9% Both Years 1 6.4 1 5.6 1 -12% 9.91 8.9 -11% 14.1 16.1 1 14% Table A5: Summer Mean Flow Com arison Springbrook Creek Mill Creek Springbrook Creek near Orillia near Orilha at SW 27" USGS 12113346 USGS 12113349 Renton GAGE SIM ERROR GAGE SIM ERROR GAGE SIM ERROR (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) 1995 3.7 2.3 -38% 4.1 4.7 16% 17.2 7.9 -54% 1996 4.7 2.4 - -48°/a 4.2 5.2 22% 7.4 8.7 170,,, Both Years 4.2 2 A -44% 4.1 1 4.9 1 19% 1 12.3 8.3 -3 3 % 19 Appendix B: Synthesized Auburn Control Flows for Pre- 1962 Period Figure 131. Synthesized Regulated and Observed Flows at Auburn, February, 1951 20000 --... . -- 18000 16000 14000 - N U m 12000 - O tV , u 10000 _N 8000 a - ♦ x 6000 4000 2000 0 2/7/510:00 2191510:00 21111510:00 2/13/510:00 2/151510:00 2/17/510:00 2119/510:00 Date Observed Q - Regulated Q per COE Guidelines Figure B2. Synthesized Regulated and Observed Flows at Auburn, November, 1959 28000 -� ----- —___ 26000 24000 - 22000 20000 -- 18000 a 16000 L 14000 12000 = 10000 • 8000 • • 6000 • • 4000 • 2000 • 0 11/19/59 0:00 11 /21/59 0:00 11 /23/59 0:00 11/25/59 0:00 1127/59 0:00 1 M9159 0:00 12/1/59 0:00 Data Observed Q - - Regulated Q per COE Guidelines 20 8 Appendix C: Future Land Use Analysis and Modeling A model based on future build -out conditions was also constructed as part of this project, but was not referenced in the hydrology memorandum submitted to FEMA. In this future conditions model, the drainage system of Springbrook Creek is assumed to be the same as under current conditions. Only land use has been changed to reflect build -out conditions. Build -out conditions were based on zoning map information provided by the cities of Renton and Kent and by King County. A future land -cover GIS coverage was generated by combining parks, wetlands, zoning, and current land -cover GIS data and applied to the model using the following four rules: 1) all jurisdictionally designated wetland areas are modeled as wetland regardless of any underlying zoning, 2) wetland soil areas indicated by surficial geology coverages are assumed to be developed based on zoning if the area is not in a jurisdictionally designated wetland, 3) all parks area (and publicly owned area in Renton) is modeled with its current land cover, and 4) future land - cover is always at least as intensive as existing land cover. The methodology for determining HRU acreages for each subbasin was similar to that of the current -conditions model with one exception; the areas that experienced a change in landuse were routed to a separate storage area from those that did not. This was added so the model could be used in future projects to add storage with new development. A summary of the acreages of each HRU by major subbasin is provided in the table below. Table Bl: Summary of HRU Acreages by Major Subbasin- Future Land Use Subbasin EIA TF (ac) (ac) TG (ac) OF (ac) OG (ac) W (ac) AF (ac) AG (ac) Water (ac) Total Area (ac) S ringbrook 2717 62 496 0 3 443 55 457 4232.5 Rolling Hills 460 32 409 0 7 1 1 0 1 17 925.7 Panther 621 85 837 0 1 1 117 1 6 33 1700.3 Upper S rin brook 132 58 279 26 29 48 0 2 573.8 Garrison 694 144 1381 0 0 116 0 3 2338.2 Lower Mill 2418 0 0 0 0 361 42 661 3481.8 Middle Mill 818 7 94 0 0 1 53 101 203 1184.9 Upper Mill 602 75 755 0 0 90 2 9 1531.8 Basin Sum 8461 462 4284 27 38 1228 110 1359 33 15968.5 Basin % _ 53.0% 2.9% 126.8% 0.20/6 0.2% 7.7% 0.7% 9% 0.2% 100.0% The future conditions model was applied in the same manner as the current conditions model to determine conveyance and storage controlled events under future conditions. The results of the future conditions analysis are shown in Tables B2 and B3 as follows: 21 Table 112: Peak Inflow to Forebay for Conveyance Limited Storm Events, Future Conditions Return Period Flood Frequency Analysis' (efs) Simulated (efs) Multiplier Date of Simulated Event 2 840 846 0.99 12/15/1999 10 1136 �1110 1.02 2/7/1955 25 1270 1276 1.00 _ 2/8/1951 50 1388 1329 1.04 1/9/1990 100 1495 1329 1.12 1/9/1990 'Flood Frequency quartiles estimated from the simulated peak flow data using Bulletin 17B procedures 2Multiplier to scale simulated hydrograph to match estimated flood frequency quantile Table 113: Storage at Forebav for Stora ze Limited Storm Events, Future Conditions Return Estimated Stage Simulated Event Date of Period l Frequency Quantiles (acre-ft) 2 Multiplier Simulated (years) (acre-ft) Event 25 131 126 1.01 2/ 10/ 1951 50 301 139 1 1.25 12/7/1975 100 641 620 1 1.02 2/8/1996 'Used Gringorten plotting position to define event return period 2Multiplier to scale simulated hydrograph to match estimated flood frequency quantile 22 Black Ri' er Pump Stati n SR-518 SR-405 '�xi Xx Upper LPanther /�. Springbrook Creek Lake Q Wl Creek" K t i _ S 212fii SL Kent Lagoons SR-516 Upper Mill Creek Legend Stream Study Reach Railroad Road Basin Boundary Scale 1"=3500' feet 21164 3500 0 3500 7000 eArStudy ea Springbrook Creek FIS Vicinity Map Major Study Sub -Basins northwest hydraulic consultants inc. Date: 11/14/2003 IFigure, 1 V R EN T CA4 I if If S' _j if PPING '77--n If NJ ��S" 4S \CE4TER L__j MORk'�' A" w ROIL PA*Qn - i� Gli 1 & -� C'qt - L_ .2 0 Od fqt,tip , , .44 X1 7— T _q A U110. '�, -&x 9 OVERFLOW 41 (584 * I I - I 'y a i:151 L C:�-j I I (( a- VALLER I S101 2005 GENERAL (AA&C) TA L A� -3 -A CREEK WIEUM OT CP s-, If f.AtRLER W11 53 L R107 W11a KT: Wib 2003 X 44 5 3( q to 11131" 5 I'M, VALU7( V) I C VALLEY RID I i Sb17 2013 zvl .39 1 Sb . ti-, I .. . I 1 0 _Z j- ;.- I 2016 W3 W1b v- V) ir W1 a If 4 6 (FOR ALT 2 Ot� bkrSb2, j Sb4 J1 ;C' f 1 2008 2009 11 2006 01 1 4D Llt _OPTI 14A 4@5 AV L' SWI C-1 J ,g SENECA V- 08 �\A/ 118 T11-41 5 b ±�5 1-r W8 I V I. *- 0Sb1 .201 i0.,;'2011 25 2 J-. 114)MAS AV I V" SCALE 1 -1000' L b7 37 15 17. V; Cr 201' Q 18 26 i�.' 16 ES 'I,' '00VkLL AV SW•17,1 f4f;,�', 17 W9 W7b 10 rr OD BLACK RW7c (0Af(t-4)A: Ju 1b MVM CHAANEL R2 2014 12010 201 5 LEGEND 7c� 2020 31 k ;. 2021 < 4 —It CULVERT(S) FEQ PIPE BRANCH NO 2 R10 HYDROGRAPH INPUT LOCATION f HSPF REACH D3� R.3 3 N I Fil 2002 H \ '-4 rl -, \' 36r DIAMETER STORM DRAIN DSN STREAMI/DiUMAGE CHANNEL Sb5 W. -\ FEQ WETLAND NO I HYDROGRAPH INPUT LOCATION CC: FEQ CHANNEL BRANCH NO 1 Q SPIF SUB BASIN DSN @ I J DSN H 33 InIt ! jO 2019 35 WILL bl CREEK fl 04 o 1. % 202 2007 4 R51 PL#op- sTA'nON 36 '2001 x RENTON C umrrs EXACK,,\ 7 Springbrook Creek FIS RIVER VALLEY Zip — PUMP FEQ Model Schematic STATION N northwest hydraulic consultants, inc. modified from East Side Green Watershed Plan TO GREEN -I) AMISH RIVER Hydraulic Analysis Report, RW Beck (1996) 11/14/2003 Figure 2 _ Water 21164 Scale 1"=3500' feet 3500 0 3500 7000 er Stay Area BRPS 7 13 Springbrook Creek 17 107A 101 15 nhe[Renton : 21 at SW 27th 1076 23a 25 27 23b 31 USGS USGS 12113 Panther Creek 12113349 29 Uppef....... 33 Springbrook Creek 53 205 35 207 55 Pe ... , 2 3205 571 Lower Springbrook Creek Mill Creek in209 39 63 \ GRNRA 61 (Kerd-lagovas) . 65 67 37 81 81 87 PSMoui " a. 89 93 P"— Pond 85 Middle 401 Mill Creek 89 403 cao> Legend Sub -Basin (ID�— Reach ID Lake/Welland Calibration Strearrdlow Gage 109 ...... 41 � 303 307 \.y 301 311 315 317 311 DOT Pond 313 309 Garrison Creek 321 319 326 381 333 335 43 323 .... . 407 Upper rPpAWW. Mill Creek 407 PeMous U.M. Pond - 405 405 ................ 1 , ,ByWmilaffire still , 1X92 twil 1 �7mmmmm..�l������.� WEIBUL/ 11 �i���.f / .i►I.S Feb. 8,19961 „1 .f Mar. 5.1972 owl .m 1 1/ 1a w 01OEM .,, �---■■■■■tea■■■■■■a ■■■■■■■ ■■ ■■=* moon ONES •. ��■■■■■■■moo■■■ri■■a ��■■■■■■■moo■■■■■■a „ ��■■■■■■■tea■■�■■■a ��■■■■■■■tea■ ■■a '��■■■■■■■moo■■■■■■a n111„II. ......,...... Iflsi>u���■■■■■■■■a ��■■■■■■■moo■■■■■■a . ■ • - I I • • • ' I M= ■ii� MO'���i�i_ii� • "• i�iii�-� iii� \iit ■■i � i i i0- ■i�iii����MOM�i��� ■iiiii��sa�i�iil7\ ■iiiii���1•�i�iiif..l ■i�iii�����i�iii� ' - �iii� Mo. iiit �i�'aii� - �i�iii� -� �i�ii i���t•���ii i it -��im �1•l/i�iii� -��iM =MO i ME i�i���l�� �i�iiit -��iEMiii�-�Is���i -�mmoimmii - -�i,imiiim IMMM - �i �t•� -���ii���iii� i iiiiMENMEMEM il�iiit i- iim li fiifii6iif i0iiiiiiiifiiOPi � mil• i iii� GGGGGGGiiGGGG G G •i G Illsillm i�� ■ e __ �� • • • - • ' • ���� iii� �iiiii=�� -��i�iii= -� ��� �iiit - i��l��i�iii� it - OfC-�1•�i�iiit mmm - ���i�iii� MMEi / =R / 11 tA_WV-'7_ 7. PROlip A ZF Q v mrjl!�i 7 TAf IF IL V� b6 --4r- fi_ - Winmm-- 7-- k�r j TIP 6- FIL-W A VMi L TexL-=s lis_p J-1t IP Atm'O wh i J-1 S _16 rv=e V rIlL 4. el —161 7! 7 0- 4r- -T. Ir - It& Ae L 'MC 7 ILA % L L. A. 1�54 A7- -A— IFJ I S j6k I L o L . 19 rff L :06 r J; 7 A tO Memorandum To: Allen Quynn, City of Renton and Mike Giseburt, R.W. Beck From: David Hartley, Northwest Hydraulic Consultants Date: October 25, 2005 Attachment: Data Model_Comparison.xls Re: Review of Springbrook Creek HSPF Calibration and Gage Records Introduction The purpose of this memo is to present data and clarify questions related to the calibration of the Springbrook Creek basin HSPF model. Specifically, the memo clarifies the status of the Green River Natural Area storage during the calibration period, presents all storm hydrograph data and simulated hourly discharges at four sites during the calibration period, discusses differences between simulated and gaged flows, and assesses probable effects of these differences on the base flood elevation modeling for the 100-year storage event. Status of Green River Natural Area (GRNA) Storage The GRNA storage was not included in the model version used to perform HSPF calibrations. The calibration period was October 1, 1994 through September 30, 1996, i.e. water years 1995 and 1996. A review of drawings and correspondence with City of Kent indicate that the GRNA storage came on line some time during the summer of 1996, after the storm season had ended for water year 1996. The last storm used for calibration took place in April of 1996. The GRNA therefore had no effect on storm hydrographs used for calibration and appropriately was not represented in the basin model used for calibration. Review of Gage Records and Model Performance This section presents a review of gage records at four stream gaging sites. Sites include the USGS gaging stations on Springbrook Creek (12113346) and Mill Creek (12113349) upstream of the study area, the SW 27`h Street Gage within the study reach monitored by NHC during the calibration period, and the total inflow to the Black River Pump station (BRPS) forebay at the lower end of the study reach. The BRPS inflow hydrograph record was derived from reverse -routing using data reflecting BRPS stage, storage, and discharge. 6/12/2006 Simulated hydrographs were developed using a single rainfall record form the USGS rain gage site associated with stream gage 12113346, Springbrook Creek near Orillia. This site is centrally located within the 25-sgaure mile Springbrook basin. The appendix to this memo presents four pages of graphs (two graphs per page) for each of four gaging stations representing the storms in the 1995-1996 calibration period. Stations are ordered from upstream to downstream beginning with the USGS site on Springbrook Creek near Orillia and ending with the inflow to the Black River Pump Station (BRPS) forebay. Both gaged and simulated hourly data for the entire calibration period are presented in an EXCEL spreadsheet entitled Data_Model_Comparison.As that have been transmitted with this memo. Springbrook Creek near Mill Creek Confluence (USGS gage 12113346) As noted in the hydrology report USGS rated records poor for both Water Years 1995 and 1996. Model agreement with the nine largest floods in the calibration record is uneven ranging from very good for the events of November, 1994 and April 1996, to poor for February and late November, 1995 (see pages A-2 through A-5). Gaged peaks and volumes are both over and under estimated by the model. During February, 1996 the simulated hydrograph tracks the gage record very well except that the peak discharge is underestimated by approximately 25% and the ranks of the double peaks are reversed compared to the record. The lower peak and volume in the simulated second peak at this site is consistent with the underestimation of the recession that occurs downstream at SW 27' Street. Mill Creek near Mouth (USGS gage 12113349) As noted in the hydrology report USGS rated records poor for Water Year 1995 and fair for Water Year 1996. The model generally tracks the gage record during the storm events in the calibration period (see pages A-6 through A-9). The model appears to be biased high for both volumes and peaks in most events, but not to an extreme degree. For the February 1996 event, the model appears to peak early and higher than the gaged hydrograph. Similar to the situation on Springbrook Creek, the second peak is the higher of the two in the gage record in contrast to the simulated hydrograph which exhibits a higher first peak. The recession of the simulated hydrograph lacks a moderate amount of volume compared to the gaged hydrograph. NHC-Operated Gage at SW 27t' Street This gage site included two float -driven shaft -encoder stage sensors on the upstream and downstream sides of the culvert crossing. The primary sensor was the upstream sensor. Below a threshold downstream depth, hydraulic analysis indicated that the culvert was inlet -controlled and a single rating curve was used to determine discharge. When downstream stage was above the threshold, the culvert was outlet -controlled and a double rating curve was used which provided a discharge estimate based on the both the measured downstream and upstream stages. The quality of data at this site was generally good; however, during some storm events the float cables did not operate freely and occasionally batteries failed. 6/12/2006 2 As shown by graphs on pages A-10 through A-13, simulated and gaged hydrographs are in general agreement during the largest storms in the calibration period. More often than not, the model predicts peaks that are somewhat larger than recorded peaks. The graph of the February, 1995 event shows that the model does a very good job of tracking a double - peaked hydrograph. During the event of record, in February, 1996, the model exhibits a somewhat shorter and earlier peak on February 80' in the afternoon compared to the measured peak which occurs on the morning of February 9th. Note that this model behavior is conservative because pump station discharge is most limited during the late morning and afternoon of February 8r". During the recession portion of the hydrograph, the model appears to underestimate recorded discharge; however, this is not particularly significant because allowable pumping at the BRPS never falls below 960 cfs after 4:30 p.m. on February Bch as shown in Figure 1. Note that the gage at SW 27th failed on the evening of February 10, probably because of a low battery. BRPS Allowable Pumping Rate Event of February 8-12, 1996 1800 1600 in 1400 LL U d 1200 1000 a � 800 IL d � 600 3 0 Q 400 200 2/7/96 2/7/96 2/8/96 2/8/96 2/9196 2/9/96 2/10/96 2/10/96 2111/96 2/11/96 2/12/96 Date Figure 1. Allowable Discharges per POPP The April 24, 1996 (page A-13) event illustrates what appears to be a problem with the gage record. The model tracks the measured hydrograph extremely well on both the rising and falling limb. During the peak, the gage record rises in a rapid and unrealistic manner that is inconsistent with both upstream and downstream gaged hydrographs data as well as precipitation records. The source of the gage anomaly is unclear; it may reflect debris that built up at the entrance to the culvert and was subsequently cleared. In any 6/12/2006 3 case, the apparent underestimation of peak and volume by the model for this event is spurious. Black River Pump Station (BRPS) Forebay Inflow The Black River Pump Station (BRPS) inflow record was calculated from forebay water surface elevations and pump station records of the times when specific pumps were turned on and off. Forebay stages were converted to storage volumes using forebay bathymetry and pump station records were converted to discharges using pump rating curves. Pump station storages and discharges were then used to estimate total BRPS inflows using reverse -level pool routing. Data are considered to be reasonably good for most of the large events, although there are some gaps in the raw data and some oscillation in the calculated BRPS inflow record resulting from the numeric instability of reverse -routing. Calibrated model fit to observed data at the BRPS are generally very good and do not exhibit an overall bias toward under -estimating peaks or volumes (see pages A-14 through A-17). In fact it looks like the contrary maybe true when all of the large storm events are examined. For the February 1996 event, the fit is generally excellent through most of the inflow hydrograph and the peak period is matched very well. There is a moderate underestimation of inflow to the BRPS during the recession from mid -day on February 9 onward; however, this would have a negligible impact on the maximum BRPS stage and storage because the allowable pump rate and pumping capacity both exceeded the inflow rate during this time period. In fact, as noted earlier, because simulated inflows are higher than gaged inflows during the constrained pumping period on February 8 and the morning of February 9, it is very likely that modeled maximum BRPS stage and storage are biased high for this event. Effect of Spatially -Varied Precipitation on February, 1996 HSPF Simulation Results The southern portion of King County generally received more rain than the northern portion of the county during February 1996 event. There are several King County rain gages within or adjacent to the basin. Application of precipitation inputs from multiple rain gage sites to better reflect the spatial variability of the February, 1996 storm results in a moderate improvement in the agreement with the gaged hydrographs for this event. For results, please see pages A-18 and A-19 of the attached appendix. Gage records used to generate simulate results in the following graphs were King County gage 54W near Lake Meridian for Upper Mill Creek and Garrison Creek subbasins, and King County gage 03U near Panther Lake for Panther Creek and Rolling Hills subbasins. The remainder of the basin was modeled using the USGS gage record as in the earlier calibration. Summary and Conclusions Comparisons of modeled and gaged hydrographs during the calibration period have been presented and discussed. The model appears to be well calibrated. Most of the 6/12/2006 4 discrepancy between the simulated and recorded hydrographs during the February, 1996 event is likely due to spatial variability of rainfall. In spite of the lack of perfect fit between model and gage records for the largest event in the calibration period, the results are conservative because the model predicts higher discharges than were recorded in Springbrook Creek and entering the BRPS forebay during the critical time when pumping water to the Green River would be most restricted under the POPP. Lower base flood elevations predicted by this study are not a result of modeling error or bias. On the contrary, the model and procedure for estimating BFEs are conservative. The lower BFEs calculated by the study compared to the effective FIS derive from two primary changes in the basin since the effective FIS was conducted- the pumping capacity of the BRPS has doubled and there have been conveyance improvements along Springbrook Creek. Of these two causes, the increase in pumping capacity and resultant ability to lower tailwater in Springbrook Creek is probably the most significant factor in lower BFEs in the downstream portion of the study reach. 6/12/2006 5 Appendix A: Graphs of Data and Simulated Storm Hydrographs 6/ 12/2006 A-1 240 200 160 120 80 40 lJ 240.- 200.- 160.- 120.- Springbrook Creek USGS Gage Site above Mill Creek Confluence — DSN 104 R33,1996 CONDITIONS SPRG CK AT LISGS SITE ---------- DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) ........... ................ .............. . ..... ...... ti 'd1\ 1,9 914 19 914 1�9 914 1�9 94 NOV 27 NOV 28 NOV 29 NOV 30 Data from 1994 DSN 104 R33,1996 CONDITIONS SPRG CK AT L)SGS SITE DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) T I I I ...................... ................ .. . ....... ........... .. ................ ..... . . .. ........ - ----- r U. 22 29 DECEMBER JANUARY Data from Water Year 1995 L? L? 6/12/2006 A-2 240. 200. 160. 120. 80. 40. 240 200 160 120, 80. 40, DSN 104 R33, 1996 CONDITIONS SPRG CK AT USGS SITE DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) 12 24 12 24 12 24 12 24 12 24 12 24 12 4 12 EB 15 FEB 16 FEB 17 FEB 18 FEB 19 FEB 20 FEB 21 FEB 22 Data from 1995 — DSN 104 R33, 1996 CONDITIONS SPRG CK AT USGS SITE L ------ DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) 12 24 12 24 12 24 12 24 12 24 12 24 12 4 12 40V 8 NOV 9 NOV 10 NOV 11 NOV 12 NOV 13 NOV 14 NOV 1 Data from 1995 6/ 12/2006 A-3 240.- 200.- 160.- 120.- 80.- 40.- DSN 104 M3,1996 CONDITIONS SPRG CK AT USGS SITE DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) ........... ............... ......... .............. Lk ti Lti 4 .... ............ - -------- 0. 6 12 18 24 6 12 18 )4 6 12 18 214 6 12 18 24 NOV 27 NOV 28 NOV 29 NOV 30 Data from 1995 240.- 200.- 160.- 120.- 80.- 40.- DSN 104 F03,1996 CONDITIONS SPRG CK AT USGS SITE DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) -.1 ... - ........... F.... " I, . Il I 1 1. -.1-7 .............. ........ ....................... ................... ....................... ................... ........ . ............ . . . ....... . ......... ....... ........... ...... .... .. . ... ....... . .......... U 12 ' 214 12 24 12 24 12 A 12 24 12 24 12 24 12 2. JAN 18 JAN 19 JAN 20 JAN 21 JAN 22 JAN 23 JAN 24 JAN 25 Data from 1996 6/12/2006 A-4 .M M WON — DSN 104 R33, 1996 CONDITONS SPRG CK AT IJSGS SITE L --- DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) J � L - 0. 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 FEB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 280. 240. 200. 160. 120. 80. 40. 0. DSN 104 FW, 1996 CONDMONS SPRG CK AT USGS SITE L DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) 20 21 22 23 24 25 26 27 28 29 30 APRI L Data from 1996 6/12/2006 A-5 240 200 160 120 80 40 Mill Creek at USGS Gage Site near Mouth DSN 119 R51, 1996 CONDITONS, MILL CK AT USGS SITE L DSN 26 Nill Creek near mouth at Orillia 12113349 (flow) s a� 0. 12 24 12 24 12 24 12 24 NOV 27 NOV 28 NOV 29 NOV 30 Data from 1994 240. 200.- 160.- 120: 80. 40.- DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE L DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) 1 V 1 ----- ..__--- --- — --—.......... .... _....._.._.._..._.....__k U. 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 DECEMBER Data from 1994 6/12/2006 A-6 240. 200. 160. 120. 80. 40. 240 200, 160, 120. 80. 40. DSN 119 R51, 1996 CONDITONS, MILL CK AT USGS SITE DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 L FEB 16 FEB 17 FEB 18 FEB 19 FEB 20 FEB 21 FEB 22 FEB 23 Data from 1995 DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE L --------- DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) NOV 9 NOV 10 NOV 11 NOV 12 NOV 13 NOV 14 NOV 15 NOV 1 E Data from 1995 s 6/ 12/2006 A-7 240.- 200.- 160.- 120.- 80.- 40.- DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE L DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) ......_.- ........ - ..........— --- — - — r � 4 a U. 12 24 12 24 12 1 24 12 24 NOV 27 NOV 28 NOV 29 NOV 30 Data from 1995 240. 200. 160. 120. 80. 40. 0. DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE L DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) ._.._...___-.._--• •- . r.••�-ems- '-----.�__-..._...__---..__...-----..-.._ r .ti 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 JAN 18 JAN 19 JAN 20 JAN 21 JAN 22 JAN 23 JAN 24 JAN 25 Data from 1996 6/12/2006 A-8 M 0 1'1 0. 280. 240. 200. 160. 120. 80. 40. DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 2 'EB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 DSN 119 R51, 1996 CONDITIONS, MILL CK AT USGS SITE DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 2 ,PR 21 APR 22 APR 23 APR 24 APR 25 APR 26 APR 27 APR 28 APR 29 APR 30 Data from 1996 6/ 12/2006 A-9 M M n e M M M w SW 27th Street Gage — DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L ---- DSN 91 SPRINGBROOK CK. AT SW 27thST (observed) R 17 1R 24 6 17 1R 74 6 17 1A 24 NOV 28 NOV 29 NOV 30 Data from 1994 DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L DSN 91 SPRINGBROOK CK. AT SW 27th ST (observed) 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 DECEMBER Data from 1994 6/12/2006 A-10 w w 4� M M M a - DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L DSN 91 SPRI NGBROOK CK. AT SW 27th ST (observed) , r r 12 24 12 24 12 24 12 24 12 4 12 24 12 24 12 24 DEC 24 DEC 25 DEC 26 DEC 27 DEC 28 DEC 29 DEC 30 DEC 31 Data from 1994 DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L --------- DSN 91 SPRINGBROOK CK. AT SW 27th ST (observed) FEB 16 FEB 17 FEB 18 FEB 19 FEB 20 FEB 21 FEB 22 Data from 1995 6/ 12/2006 A-11 RON Riill �l DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L DSN 91 SPRI NGBROCK CK. AT SW 27th ST (observed) , r . ........ . - ----- r 12 24 12 24 12 24 12 24 12 24 12 24 12 4 12 2� 1910A NOV 8 NOV 9 NOV 10 NOV 11 NOV 12 NOV 13 NOV 14 NOV 15 Data from 1995 DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE L ------ DSN 91 SPRINGBROOK CK. AT SW 27thST (observed) ti L U. 6 12 18 24 6 12 18 24 6 12 18 24 6 12 18 24 NOV 27 NOV 28 NOV 29 NOV 30 Data from 1995 6/12/2006 A-12 M 190d M WO 0. 500. 400. 300. 200. 100. DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE DSN 91 SPRI NGBROOK CK. AT SW 27thST (observed) 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 2 DEB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 DSN 191 R21, 1996 CONDITIONS SW 27 GAGE SITE DSN 91 SPRINGBROOK CK. AT SW 27thST (observed) 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 2, PR 21 APR 22 APR 23 APR 24 APR 25 APR 26 APR 27 APR 28 APR 29 APR 30 Data from 1996 6/ 12/2006 A-13 400.- 300.- 200.- 100.- 0.- -100. WE EM K "I "I's ini Black River Pump Station DSN 194 1995 TOTAL FLOW INTO BRPS, CALI B DSN21 Black R\ter Pump Station Total Inflow (data) ... .......... '4 Cis ............... . ... ... ... ........ .. e i ............. .. . ... . .......... .. . ....... 29 1 NOVENUER DECENUER Data from 1994 DSN 194 1995 TOTAL FLOW INTO BRIPS, CAUB DSN21 Black R\er Pump Station Total Inflow (data) ....... ....... ...................... ......... ............... .......... . . .... - -------------- 0. 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 DECENUER Data from 1994 6/12/2006 A-14 M 011i 100. DSN 194 1995 TOTAL FLOW INTO BRPS, CALIB L DSN 21 Black River Pump Station Total Inflow (data) ............... r U. 12 24 12 24 12 24 12 24 12 24 12 24 12 4 12 24 FEB 15 FEB 16 FEB 17 FEB 18 FEB 19 FEB 20 FEB 21 FEB 22 Data from 1995 500 400 300. 200. 100. 0. DSN 194 1995 TOTAL FLOW INTO BRPS, CALM L DSN 21 Black Peer Pump Station Total Inflow (data) 12 24 12 24 12 24 12 24 12 24 12 24 12 4 12 NOV 8 NOV 9 NOV 10 NOV 11 NOV 12 NOV 13 NOV 14 NOV 1: Data from 1995 6/ 12/2006 A-15 KIM M M MCI W RM 0 400.- KM Wil im DSN 194 1995 TOTAL FLOW INTO BRPS, CALIB DSN 21 Black R\A--r Pump Station Total Inflow (data) ........... .......... L. li ......... ........ ....... ...... .......... ....... . ... 7,-.J. N 12 24 12 24 12 24 12 24 12 24 12 24 NOV25 NOV26 NOV27 NOV28 NOV29 NOV30 Data from 1995 DSN 194 1995 TOTAL FLOW INTO BRIPS, CALI B DSN 21 Black Fiver Pump Station Total Inflow (data) ................. I .............. ........ I ....................... ...... ...... ...... . . . ................ . . . ...... . ..... ........... . .. . . ................... . . .......... 0. 1'24 - 6 .... 1 1 2 1 '8' 24 6 12 18 24 18 )4 1'8 2 12 18 24 6 12 18 24 6 12 18 24 6 1 JAN 18 JAN 19 JAN 20 JAN 21 JAN 22 JAN 23 JAN 24 Data from 1996 6/12/2006 A-16 100011 1X M 01:1 m `reAl M DSN 194 1995 TOTAL FLOW INTO BRPS, CALIB L DSN 21 Black Rimer Pump Station Total Inflow (data) l FEB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 DSN 194 1995 TOTAL FLOW INTO BRPS, CALI B L DSN 21 Black River Pump Station Total Inflow (data) APR 21 APR 22 APR 23 APR 24 APR 25 APR 26 APR 27 APR 28 APR 29 APR 30 Data from 1996 6/ 12/2006 A-17 Performance of Model During February, 1996 Using Three Rain Gage Records EQ1 KOX KID] W0111 A DSN119 R51,1996 CONDITIONS, MILL CKATUSGS SITE DSN 26 Mill Creek near mouth at Orillia 12113349 (flow) ...... ....... F, I ....................... I ...................... ....................... I ....................... I ....................... I ...................... J.- .............. ...... . ........... . ......... .. . ......... . ....... . . ------------- 500.- 19111111 �cm KIAM 10 " I 1q 1 1z /z Z14 1z /4 1z Z4 4' " 3 FEB' ' 4 FEB' "' 5 FEB' "' 6 FEB' " 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 — DSN 104 M3,1996 CONDITIONS SPRG CK AT LISGS SITE E ---------- DSN 24 Springbrook Creek at Orillia, WA 12113346 (flow) ......... ... 1 ... ................... T ............. ....... .... .......... T .......... ....... 1� ........... ...... I ....................... . . . ......... ....... . .. Lh ------------ V. I , 1. . . ' ' ' ' ' 2 24 12 24 12 24 12 24 12 24 ' 12 24 12 214 12 24 12 24 12 24 FEB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 6/12/2006 A-18 DSN 191 R21, 1996 CONDITONS SW 27 GAGE SITE L -------- DSN 91 SPRINGBROOK CK. AT SW 27th ST (obser\ted) M M M M 0. FEB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 DSN 194 1995 TOTAL FLOW INTO BRPS, CALI B ---------- DSN 21 Black River Pump Station Total Inflow (data) M M. M Pe 0. 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 24 12 2 'EB 3 FEB 4 FEB 5 FEB 6 FEB 7 FEB 8 FEB 9 FEB 10 FEB 11 FEB 12 Data from 1996 L? 6/ 12/2006 A-19 Appendix B SPRINGBROOK CREEK FEMA RE -MAPPING STUDY CROSS SECTION VALIDATION Appendix B SPRINGBROOK CREEK FEMA RE -MAPPING STUDY CROSS SECTION VALIDATION (CONT.) Appendix A MEMORANDUM To: Dick Wild, FEMA Allen Quynn, Renton From: Mike Giseburt Subject: City of Renton Springbrook Creek FEMA Remapping Study Activity 1 - Field Surveys and Reconnaissance Date: September 16, 2003 This submittal includes the work of Task 2 Field Surveys and Data Collection of the Springbrook Creek FEMA Remapping Study (agreement between R.W. Beck and the City of Renton, February 2003). It is also being submitted to FEMA to satisfy the requirements of Activity 1 — Field Surveys and reconnaissance as described in the City of Renton, Washington Cooperating Technical Partners Mapping Activity Statement. Objective The hydraulic modeling for the Springbrook Creek FEMA Re -Mapping Study will be based upon prior the FEQ model developed in 1996 as part of the East Side Green River Watershed Plan. The study reach extends from SW 43rd Street (Renton's southern city limits) north to the Black River Pump Station and includes several culvert/bridge crossings. These crossings include (from upstream to downstream) SW 43rd Street, SW 41st Street/Oakesdale Avenue, a railroad bridge, SW 34th Street, SW 27th Street, the Hunter Douglas access road bridge, Oakesdale Avenue bridge, SW 16th Street, I-405, Grady Way, SW 7th Street, and Oakesdale Avenue again. The creek splits into two separate channels just downstream of SW 16th Street and then reconnects downstream of I-405 just upstream of the Grady Way crossing. The east channel was constructed in the early 1990s as part of the City's "Connecting Channel" project to supplement the conveyance of the natural channel through this area. The west branch is the natural Springbrook Creek channel. The study reach also includes a channel referred to as the 23rd Street drainage channel that connects the Panther Creek wetland east of SR 167 to Springbrook Creek and parallels the SW 23rd right-of-way. The existing model is based upon prior field surveys and channel/culvert/bridge design drawings. Cross section data in the model came from a variety of sources including field survey by NRCS (formerly SCS) in 1990, more recent survey by W&H Pacific and R.W. Beck, channel design drawings, and 1980 COE topography. As -built information was used when available, however, many of the data sources (i.e., cross -sections) were not as -built. Table 1 shows the cross sections used in the model and the source for each. 11-00781-10000 1 C:\Documents and Settings\bsnanr\L.ocal Settings\Temporary intemet Files\OLK31\Actl submittal.doc 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 MEMORANDUM September 16, 2003 Page 2 In order to confirm that the cross sections that were not as -built describe the existing channel cross sections adequately, a validation was performed to compare cross sections used in the model and actual surveyed cross sections. Based on the comparison, recommendations were made as to whether additional survey should be performed. The stream reaches where cross sections were surveyed for validation are generally those that were based upon construction drawings and are as follows: ■ Three sections downstream of SW 16th Street where the cross sections were based upon SCS construction drawings (FEQ cross sections 2063, 2072, and 1010) ■ One section along the reach between SW 16th Street and the new Oakesdale Avenue Bridge, where the cross sections were based on design drawings for the channel widening in this area but'no as-builts are available (FEQ cross section 9007) ■ Two upstream of SW 41st Street, where cross sections were based on channel widening design drawings which were part of the Oakesdale Business Park development (FEQ cross sections 2077 and 2091). The Figure 1 shows the location of the cross sections selected for the validation. The following sections describe the survey and observations results, followed by conclusions and recommendations. In addition to the validation, a field reconnaissance of the study reach was conducted. The purpose of the reconnaissance was to note any change in roughness or additional hydraulic features that have been added since the existing hydraulic model was developed. Results Field Reconnaissance The field reconnaissance of the study reach was conducted on March 27, 2003 by R.W. Beck and Northwest Hydraulic Consultant (nhc) staff. No changes in any hydraulic structures were observed. However, field observations indicated that channel roughness had changed since the existing hydraulic model was developed in early to mid-1990. The estimated roughness coefficients based on the field observations are shown on the photographs contained in Appendix A. Cross Section Validation Appendix B contains figures illustrating the cross section comparisons described in the following paragraphs. 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 6954701 MEMORANDUM September 16, 2003 Page 3 Starting at the downstream -most cross section, Section 2063, which is just upstream of the first Oakesdale Bridge crossing and downstream from SW 7th Street. The surveyed cross section generally matches well with the FEQ cross section except that it appears that the low flow channel has filled in. In addition, it was noted during the field reconnaissance that the channel reach immediately downstream of this section becomes narrower. For example, the low flow channel width narrows from approximately 40 feet to 20-25 feet. Narrowing of the channel cross section is not reflected in the FEQ modeled cross section. It is uncertain whether the narrowing of the channel was due to sedimentation over time or that the channel was not built to its actual design. The next cross section, Section 2072, was taken from design drawings and does not correspond very well with the surveyed cross section. In addition, Springbrook Creek has developed islands in this area that are not reflected in the modeled cross sections. Section 1010 is on the natural Springbrook Creek channel upstream of Grady Way, just downstream of the I-405 Bridge. The surveyed cross section appears to correspond fairly well with the cross section that was used in the model. However, it was noted in the field that a there is no moving flow in the natural section of creek. The majority of Springbrook Creek flow now goes through the east branch (connecting channel) downstream of SW 16th Street. It appears from the design drawings, that flow was intended to be split between the two channels. It is likely that some sediment build up has occurred in the natural channel section between SW 16th and I-405 that confines flow into the connecting channel. Section 9007 is just downstream of the second Oakesdale Bridge crossing and upstream from SW 16th Street. The surveyed cross section and modeled cross section correspond fairly well at this location, except the lower portion of the channel. It is noted that the design drawings for the channel widening of this reach (Oakesdale Avenue SW Extension Phase 1, 1997) did not include topographic cross sections that describe the channel below the water surface. Therefore, the FEQ modeled cross section had been developed using a combination of the prior cross section information (SCS survey) for the lower portion of the channel and the channel widening design plans above the water surface. Section 2077 is upstream of SW 41st Street and the culvert at the entrance to the Oakesdale Business Park. The cross section used from the model was based on cross sections developed for the Oakesdale Business Park Development. As part of the Oakesdale Business Park development, a high flow bench was excavated into the creek channel between SW 41" Street and SW 43`d Street. The surveyed cross section is reasonably close the modeled section, however the modeled section is generally wider and the bottom invert is higher. Section 2091 is downstream of SW 43rd Street and in the same Oakesdale Business Park Development. Similar to Section 2077, the modeled cross section is slightly wider and the bottom invert is higher than the recently surveyed section. It is recognized that some differences between the modeled cross section and new surveyed cross sections would be likely. However, the extent of the differences, particularly downstream of SW 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 6954701 MEMORANDUM September 16, 2003 Page 4 16th Street is fairly large, particularly given the observation that downstream of Section 2063, the channel section significantly narrows which is not reflected in the model. The differences in the cross sections near the Oakesdale Business Park were less significant than those downstream of SW 16th Street. In addition, these cross sections are located at the upstream end of the study reach such that any changes in conveyance at these locations would have little impact on the water surface elevations in the study reach. Therefore, it was concluded that these cross sections in the model were acceptable for this study. Sensitivity Analysis Due to the differences in the surveyed and modeled cross section downstream of Grady Way (2072), a sensitivity analysis was performed using an existing HEC-RAS model of the area which uses the same cross sections as the FEQ model. The sensitivity analysis was performed to see if the differences in the cross sections had a significant effect on the water surface profiles. The HEC-RAS model was used instead of the FEQ model for the sensitivity analysis because it is simpler to use and is an excellent tool for comparing the conveyance of two different channel cross sections. The existing HEC-RAS model reflects the "Conveyance" condition on Springbrook Creek rather than the "Storage" condition. In other words, it uses the 100-year peak flow with a tailwater condition that reflects the Black River Pump Station operating with no pumping limitations. The HEC-RAS model was modified by using surveyed cross sections 2063 and 2072. The resulting water surface elevation at cross section 2072 (Elevation 8.12) was more than a foot higher than in the original model (Elevation 7.12). The higher elevation continued upstream, although the increase in elevation decreases as you move upstream. This difference in simulated water levels is greater than the desirable accuracy of the modeling and therefore modifying the existing FEQ model in the lower stream reaches and conducting some new survey of cross sections in this area was recommended. Although new survey was recommended, it is noted that the ultimate floodplain elevation in the downstream portion of the stream system will be likely based on the "storage" event rather than the "conveyance" event. A "Storage" event represents an event that happens during a period of high water levels in the Green River such that the Black River Pump Station has to reduce pumping rates or shut down. Some consideration was given to not updating the model and cross sections since this portion of the system may be dominated by the "storage" event. However, this was not recommended because it is uncertain where the point of transition (floodplain determination switching from "storage" to "conveyance" events) will be. In addition, such a difference in cross sections may also lead to a poorer hydraulic model validation. Therefore, it was recommended that new cross sections be surveyed for the portion of the system between the upstream end of the forebay to SW 16th Street. 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 6954700, Fax (206) 695-4701 MEMORANDUM September 16, 2003 Page 5 Supplemental Survey Based on the results of the cross section validation, the reach of Springbrook Creek from the upstream end of the Black River Forebay (about 600 feet downstream from the first Oakesdale Bridge crossing) to Grady Way was re -surveyed. In addition, the natural Springbrook Creek channel between Grady Way and the SW 16th Street bridge crossing was re -surveyed. More specifically, the following cross sections were surveyed: ■ Three cross sections between the Oakesdale bridge and the forebay, ■ Three additional cross sections between Grady Way and Oakesdale and ■ Two additional cross section between I-405 and SW 16th Street. The location of these sections is shown on Figure 2. One of the cross sections between I-405 and SW 16th Street was located immediately downstream of where the connecting channel begins to better describe the channel split in the FEQ model. All of the surveyed cross sections were tied to one of the permanent bench marks (NAVD 1988 Datum). The survey results are included in Appendix C. These new surveyed cross sections will be used to update the existing FEQ model between the pump station and the SW 16`h Street. c: David Hartley, NHC 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 Springbrook Creek FEMA Re -Mapping Study Cross Section Data Sources Table 1 BRANCH NODE ID CROSS LOCATION CHANNEL DATA SOURCE NO. SECTION IDENTIFIER INVERT NO. ELEVATION 72 PSFORBYD 2050 pump station -8.5 SCS forebay "As -built" construction drawings PSFORB10 2051 -4.75 SCS forebay "As -built" construction drawings PSFORBY9 2052 -3.8 SCS forebay "As -built" construction drawings PSFORBY8 2053 0 SCS forebay "As -built" construction drawings PSFORBY7 2054 0 SCS forebay "As -built" construction drawings PSFORBY6 2055 -2 SCS forebay "As -built" construction drawings PSFORBY5 2056 -2 SCS forebay "As -built" construction drawings PSFORBY4 2057 0 SCS forebay "As -built" construction drawings PSFORBY3 2058 -2 SCS forebay "As -built" construction drawings PSFORBY2 2059 -2 SCS forebay "As -built" construction drawings PSFORBYI 2060 -2 SCS forebay "As -built" construction drawings PSFORBYU 2061 0 SCS forebay "As -built" construction drawings 1 SBRKAD 4010 -0.61 RW Beck Survey, 2003 SBRKAU 4012 -0.74 RW Beck Survey, 2003 4 SBRKBD 4012 -0.74 RW Beck Survey 2003 SBRKBI 4014 0.18 RW Beck Survey 2003 SBRKBU 4015 1.309 RW Beck Survey 2003 RW Beck Survey, 2003 5 SBRKCD 4015 1.309 RW Beck Survey, 2003 SBRKC4 4016 1.47 RW Beck Survey, 2003 SBRKC3 4018 1.16 RW Beck Survey, 2003 SBRKC2 4019 -0.31 RW Beck Survey, 2003 SBRKCI 4020 0.782 RW Beck Survey, 2003 SBRKCU 2074 Grady Way d/s 1 RW Beck Survey, 2003 6 SBRKDD 4028 Grady Way u/s 0 RW Beck Survey, 2003 SBRKDI 4021 0.999 RW Beck Survey, 2003 SBRKDU 4022 -0.51 RW Beck Survey, 2003 7 SBRKED 4022 -0.51 RW Beck Survey, 2003 SBRKEU 4025 1.39 RW Beck Survey, 2003 9 SBRKFD 4027 1.39 RW Beck Survey, 2003 SBRKFU 4027 16th d/s 1.39 RW Beck Survey, 2003 10 SBRKGD 9004 16th u/s 1.5 Oakesdale Avenue SW Extension Phase 1 Record Drawings (December 1997) SBRKG3 9004 1.5 Oakesdale Avenue SW Extension Phase 1 Record Drawings (December 1997) SBRKG2 9005 1.5 Oakesdale Avenue SW Extension Phase 1 Record Drawings (December 1997) OAKBRD 9010 Oakesdale Br d/s -0.23 WH Pacific Survey (1999) OAKBRU 9012 Oakesdale Br u/s -0.81 WH Pacific Survey (1999) SBRKG1 9014 -2.58 WH Pacific Survey (1999) SBRKGU 9021 -0.24 WH Pacific Survey (1999) 13 SBRKHD 9021 -0.24 WH Pacific Survey (1999) SBRKH2 9029 -0.18 WH Pacific Survey (1999) SBRKH3 9030 1.09 WH Pacific Survey (1999) SBRKH4 9031 0.82 WH Pacific Survey (1999) SBRKH5 9032 -0.16 WH Pacific Survey (1999) SBRKH6 9033 -2.08 WH Pacific Survey (1999) SBRKHU 9035 0.04 WH Pacific Survey (1999) 14 SBRKID 9035 0.04 WH Pacific Survey (1999) Cross Section Data Source Table 1 Page 1 of 4 SBRK11 9036 1.41 WH Pacific Survey (1999) SBRKI2 9039 1.3 WH Pacific Survey (1999) SBRK13 9040 -0.29 WH Pacific Survey (1999) HDBRID 9043 Hunter Douglas Bridge -0.12 WH Pacific Survey (1999) SBRKI4 9052 -2.73 WH Pacific Survey (1999) SBRK15 9053 -1.75 WH Pacific Survey (1999) SBRKJU 9055 -2.24 WH Pacific Survey (1999) 16 SBRKJD 9055 -2.24 WH Pacific Survey (1999) SBRKJI 9056 -2.03 WH Pacific Survey (1999) SBRKJ2 9058 -1.74 WH Pacific Survey (1999) SBRKJ3 9065 0.77 WH Pacific Survey (1999) SBRKJ4 9069 0.32 WH Pacific Survey (1999) SBRKJ5 9071 0.45 WH Pacific Survey (1999) SBRKJU 9073 0.53 WH Pacific Survey (1999) 17 SBRKKD 9073 0.53 WH Pacific Survey (1999) SBRKKI 9075 0.84 WH Pacific Survey (1999) SBRKK2 9076 0.42 WH Pacific Survey (1999) SBRKK3 9077 1.82 WH Pacific Survey (1999) SBRKKU 9078 private bridge d/s 2.42 WH Pacific Survey (1999) 18 SBRKLD 9078 private bridge d/s 2.42 WH Pacific Survey (1999) SBRKLU 9079 1.82 WH Pacific Survey (1999) 19 SBRKMD 9079 1.82 WH Pacific Survey (1999) SBRKMI 9080 2.12 WH Pacific Survey (1999) SBRKMU 9081 27th Ave d/s 1.82 WH Pacific Survey (1999) 20 SBRKND 9102 27th Ave u/s 2.96 R.W. Beck Survey, 2001 SBRKNU 9102 2.96 R.W. Beck Survey, 2001 21 SBRKOD 9102 2.96 R.W. Beck Survey, 2001 SBRKO2 9103 3.14 R.W. Beck Survey, 2001 SBRKOI 9104 1.99 R.W. Beck Survey, 2001 SBRKOU 9105 1.8 R.W. Beck Survey, 2001 23 SBRKPD 9105 1.8 R.W. Beck Survey, 2001 SBRKPU 9106 2.97 R.W. Beck Survey, 2001 24 SBRKQD 9106 2.97 R.W. Beck Survey, 2001 SBRKQU 9107 3.34 R.W. Beck Survey, 2001 25 SBRKRD 9107 3.34 R.W. Beck Survey, 2001 SW34TH 9107 34th d/s 3.34 R.W. Beck Survey, 2001 26 SW34TH 9108 34th u/s 3.86 R.W. Beck Survey, 2001 SBRKS1 9109 2.815 R.W. Beck Survey, 2001 SBRKSU 9110 3.31 R.W. Beck Survey, 2001 27 SBRKTD 9110 3.31 R.W. Beck Survey, 2001 SBRKTI 9111 4.85 R.W. Beck Survey, 2001 SBRKTU 9112 RR bridge d/s 4.94 R.W. Beck Survey, 2001 30 SBRKUD 9115 RR bridge u/s 3.57 R.W. Beck Survey, 2001 SW41ST 9114 41st d/s 3.89 R.W. Beck Survey, 2001 31 SW41ST 2076 41st u/s 6.52 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV1 2077 6.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV2 2078 5.92 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV4 2080 6.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) Cross Section Data Source Table 1 Page 2 of 4 SBRKV3 2079 7.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV5 2081 6.82 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV6 2082 6.32 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKV7 2083 6.72 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKVB 2084 7.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKVU 2085 7.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) 33 SBRKWD 2085 7.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKWI 2086 8.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW2 2087 6.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW3 2088 6.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW4 2089 6.72 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW5 2090 7.52 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW6 2091 7.52 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SBRKW7 2092 8.32 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) SW43RD 2093 43rd d/s 6.42 Oakesdale Business Campus Phase 2 "As-builts" (November, 1999) 450 P9CHANAU 8044 5 SCS Survey 1990 P9CHANAI 8043 5 SCS Survey 1990 P9CHANA2 8042 5 SCS Survey 1990 P9CHANA3 8041 5 SCS Survey 1990 P9CHABAD 8040 5.6 SCS Survey 1990 45 P9CHAND 1300 3 Olympic Pipeline Culvert Replacement 1999 P9CHANU 1300 3.7 Olympic Pipeline Culvert Replacement 1999 46 P9CHANBD 8045 7.1 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) P9CHANBU 8046 4.1 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) 461 P9CHANBU 1300 3.91 Olympic Pipeline Culvert Replacement 1999 P9CHANBD 1300 3.91 Olympic Pipeline Culvert Replacement 1999 47 P9CHANCD 8046 4.1 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) P9CHANC2 8047 6.9 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) P9CHANCI 8048 8 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) P9CHANCU 8049 9 SCS Survey 1990 supplemented with field survey of Renton's wetland W-8 (no date given) 63 BY405AD 4024 1.36 R.W. Beck Survey, 2003 BY405AU 4026 -2.3 R.W. Beck Survey, 2003 64 BY405BD 4028 0 R.W. Beck Survey, 2003 BY405BU 4024 1.36 R.W. Beck Survey, 2003 Cross Section Data Source Table 1 Page 3 of 4 81 P9CHAN 9009 6.9 84th Street to S Grady Way Culvert Construction (July 1998) 9009 6.1 84th Street to S Grady Way Culvert Construction (July 1998) 80 P9CHAN 9008 8 84th Street to S Grady Way Culvert Construction (July 1998) 9008 6.64 84th Street to S Grady Way Culvert Construction (July 1998) Cross Section Data Source Table 1 Page 4 of 4 DO7 SW 7th St Zn7Z � rota � 1-405 SW ism St e+D5 U�5 e( /157—1005e! d 9t76 ff . 9J,3o - c 3 11595 ----�� 11775 0 Q 13935 0 OMNI ---- — L' SW 27th St G��S 5 Ec.•r1 a /� S SW aft St jv2v6YEo SY FZW F3ec!< Foia 'r'14scc Z C�nSS S,ecTT o,! Vt4 L-,OA' SW 41 st St Note: Goss section locations and extents ore approzimatn. Precise iocabon and width of cross actions can be determined from the HEC-2 input file. Apprvzhnah, Soak: Iwo a I DDa 2000 11 East Side Green River Watershed C.acgtl�o.r o F CRoSs, Stc1�� v�� r .... ENO OF FORMAY K: Maio 1AFF ,S l :r , f _ _ u , , :nvm VAll r MY••'�^M� !''. e"==_ni•",�.y.•'`� .R �`J r;�(.� t .ri^:..�^�,n ....•:.......•..,. �rYY A I Y•'� zex,'.. • �,. ,,gip � j��:�i/��// � 4 �•-�� �,,_., ,...,...<'.. ; I • .� \ u`, ,yam { ] Zo �/�y ... .a\ % w;ia:.,:w^ •��-�,. s i.op tg ` s .r: J ^: n .. < ✓i .l.'' r6e'r , : F,r .. ee F' r (� .._: t:......F>. i i A � • :i s :j a tk Ir. C Yjvvel : •i ......._.w.... 6� Lie f , 7 I ! i$ ...... Jo _ w Appendix B SPRINGBROOK CREEK FEMA RE -MAPPING STUDY CROSS SECTION VALIDATION (CONT. Appendix A y �' ..� �- .�ir,.6 -^ n-' - `.^� •fr -. fiu- +i ilye, �" ��f!� ! � •ems *S : s �..1 �.a � ' , �.j,, o� _���•�� ! }�jj jai}`` . t l� V. �,,� ci�fi� s. `..!�Y ��• 1���: �� 9 r �'�G' ����; tom. y �I fi`' t ` 5 ALI, 3Y� 3 _ met ' t � 1 1, ..�• w ,.z, _ — .`•: ► •' Y va,:-Sc r as F• y'ritc.� ��ir�� � o. ��7y.��, :._Z 7W arm vl ♦ E��� ��F, - 1S -��.'.Y v: �F - r�,:� '•yeti e ��� K r l - • At f •_� - s' ice.^ AlA Ric l. /j1 r IASit �.� `• i s ,l• RAW 'AJ Opt .,t ����'��• V+ r. S 'f``'- i�" +' y /�� f, 'f� I Al it 44 't v.i1 0•. Ott � ;. :, t a �J - ' Downstream SW 7`h Street at Treatment Plant Access Bridge. Nc=0.045, Nb=0.1 Downstream Grady Way. Nc=0.045, Nb=0.1 MOM611M., Downstream SW 16'h Street. Wall on east side. Nc=0.045, Nb=0.1. Note split channel 40 �"�InL- S .{• s. '�� � � yr ,� ��. Looking downstream from Oaksdale Bridge #2. Nc=0.045, Nb=0.1 Downstream of Hunter Douglas Bridge. Nc=0.06, Nb=0.1. These higher N-values start about 200+/- feet upstream of Oaksdale Bridge #2. dM- l s y _ �- Y � t _ s.u. r r (• e�• J � - -- - --- - ----------- �t,j.0 s eyf •;,�/� �,`i moo' , �. � \ 1� � 11 � �•. ♦ . � I +vl{ �� r_�� - 1, - ��•� j•b,�_' fC. Y ,�+,' '-1 \v��. -_ 3''''`` q-o ..«� I 1 r ��� 1 \` _ • }� 1, ~�.-s—: r�� ,>_•i ►�. i y 5'ry'i �.. s en ks ,. jr 1 r. Y t1L i • ' r I Looking downstream from P9 channel. Nc=0.03, Nb=0.05 to bend. Looking upstream from P-9 channel. Nc=0.03, Nb=0.05 for 200+/- feet. P9 channel upstream of Linde Avenue. Navg=0.08. P9 upstream of Linde Avenue Mu on i IL _ rr' w WA WrIV1,71 FA :�e. Y� � c^►��� �,' •tee. �- •..� �`f,��l�t��} , 0� I -� • r«I' r"rf I mi TLAN MIA, Ilk 10 I WR lit a 110 Alt IAI. N4 VIM_ J7 try mkt -. s� x,,<� - _i y.' s'•+�i •F�,� � w-at�1}5 � 3���'•� y �C ' �•\ :�R mil'-�itC ,,Z' i- � - .l-�� - y� ;�:ti i •'. 4�1 i3. � � ti l 'r. t, s? h'_ � ' 'lam _ �• rY ` 1/.. .$� �a�.tiwT, �E 'Ifs ��• Ate% � .ir �. y i� ' A :'� 't ^ .. i.�-`• �fit.,,{s� y ° //� 1 w -'77- owl, Jj, % ` . -� `may AMP NMI _ \F .��. -' LA- - y fly _ �,• 4aav� \=� �/yC}•v�"I1r'�1' ��r .f , � S�a1�' ,% `✓ :� H - I ';. • �� 11'^ ` `ram - � �. ' � / -iY ,. i �• 'i•°r .r_r�..�f �+�'?iF � :3+r �Ir'.�:. �:.�. 4�� ` -. _,�7���h , _'�?`.n� i S� a' : d r A �RYa i fir•-�Y{� - F •; � .. i `.P. ;d"� `r• �' - r /r- ti 1l � 'fie .} ;• _ :� 6 R .:�j�� 4�ifl•'�'y: \l I Ord ;"Ae 41 _ v oil Joe a - " '%�Ct;:y; ice• - - .�� •% -�/ J - - 'Y r. � r `mow i ��`�� r ; ` � L • f � � (L flr�� f- f a: i-1��'•tbi •ice` �� ` 1. 16h'! - .. �'^ VM, ...... .................. Tr; •=' ' r. .Y ��� �,.. �.YF _ .ti!• Sri T .+F YTS � •. � Y �• •� � )� r ►-� � 'T••'� `Y ,•, � yam' �Vr TAR-:.s� •-.+�'1--- VI- Yg; If y.� r � t • ++.�'S�.,Jb ._ r %`1 art t -- ;--• � ' -` Appendix B SPRINGBROOK CREEK FEMA RE -MAPPING STUDY CROSS SECTION VALIDATION (CONT.) Appendix B a ,o CD w 25 20 15 10 5 0 Section 2063 (Approximately 2000 feet d/s of Grady Way) -50 0 50 100 150 Station (ft) 200 Survey 2003 --- FEQ Section 2072 (approximately 175' d/s of Grady Way) 20 15 c :° 10 - � -Survey 2003 � aD w 5 iF 0 50 100 150 200 Station (ft) ,o 4a M a w 25 20 15 10 5 E Section 1010 (approximately 40' d/s of I-405) 0 50 100 Station (ft) 150 �-Survey 2003 -F FEQ Section 9007 (Approximatley 40' d/s of Oaksdale bridge) 25 20 = 15 .° 10 c� � 5 a� w 0 -5 -50 0 50 Station (ft) 100 150 Survey 2003 FEQ w Section 2077 (approximately 100' u/s of 41 st) 25 20 15 10 5 0 CIS 50 100 Station (ft) 150 --- Survey 2003 --- F E Q Section 2091 (approximately 211' d/s of SW 43rd St.) PA 20 0 15 10 a� w 5 0 0 50 100 Station (ft) 150 200 ---Survey 2003 } FEQ _� Appendix B SPRINGBROOK CREEK FEMA RE -MAPPING STUDY CROSS SECTION VALIDATION (CONT.) Appendix C Ilp s IN Is MIR IN Im IN Im -4 � IM IN Is IN Im IN i-44 IN WOMEN■MMESSESERmommommommom F■■■m■■m■■■■■■■■■■■■ n IN lillimillimilillillilli - F .p �� M1111? IIIIIINIIIIIIIIIIIN111111 - 1111 IIIIIIIIIIIINII■11■1111111 _IIIIIIIm111 111111111111111111 ,,_„ N11111111111 IIIIII111111111111 IIEII 1lZIN31�'ICIIIIIIIIIIIIIII ��, IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII IIIIIm111111111I1111111I111111 N111111 NIN111111 11 1/111111 .:;IN�'�9l1 IIIIi111111 11 11111111 IIIIIIIIIIIIIIIIIIIIIIIIIIIIII 1 111111111111111111111111111 1 1 :...■■■■■■■■■■■■■■■■■�■■■■■■■■■��■■■ -- r �mill f1 a MEN oil Ja1 Mist 1�;�!�It'��111111111111111 r ' - � "u IIG111l�!��Ii�11ic�11w11111111e111 1112011111111111111111111111111 ,M 1111111 I11111111IN 111111111 �� 11��1118111�111111111111111111 II r•n Illlllllellll�Iele111111111111111 ®� . • Isa IIIIIIIIIIIIIII11111111111111111 � •- � I 11l��11�11'i11�1i111111e111111111 •IMI111111111111111111111111111 IIIe11111111IINII11111111111111 ��� : ,�� IIIIN111 111 111 1111111 IIIIIIN III111111 EN ® IE! e11 IIIIIIII ®® IN !!l1�11111IIIIII�MINE ME 4.. i is EWEN • , i®� . 1 CIII�II�IrIp�11��1l�1��1���'!J �� � t: ®O®®� -1IIIIINNIIIIIIIIIII111111111 `���us���h�: 1141'19'�!4'pill,Ile 1�.411!�1l�' 1��1 ®® �!1® wn111��I��Cl�1��11111lIIIIIIr111111 �* . �'® � :. 11!l11�1111111��hS'1�1!!�IZShIZ -- ®_®� • L'' �� IE�'G�11�lE��LIIIIIIIIIIIIIIIIIIII ` ®®�� • : �� IIIIINIIIIIIIIIIin111111111111 � ` ®®� � . - �11111111111111111111111111111111 ��' :"� ®®��� ,,. 11111111111111111111111111111111 ' '�®®� 11!���JI�IIn1��1111111111111111111 �� �� `tt 01,1111!�!�111lIIIe�111���111111111. �®1� - � -IIIIIIi1111il1111111l1111111111! �: �®®- • : ,.: 111111111111111 1111111111111111 l., z� IE31�'lielll1�11 1�1�sONM1 ®®u■ulruuuuuu Ilesle��l1�����e����������������_ :«J} IINIIIIIINIIIIIIIIIIIIIIIIIIIi f~ Y -®�S® ..aA 111111111111111111 1111111111111 :�� ®®�� 9,� Intl 1®1111111111 IIIIIN111111 ®® IIIEI I�II11E1111� ISII11p©1111 ®�_ • -,,A IINIIIInI 11111 111111111111 w= ; ��®® ; _.j IIIIIIIINNIIIIIN 111111111111 � ft'�a�; , ®®� '11111111111111111111111111111111 �`'`��;u ` oaf t t m go M". SCA 65 H I �S woke ELEv CJr ST 4 U 90 Iq.sa 2-1 , 1, CXo 19• I { , , r • i : _..�;___{..__ _.,..�.... _ _....•_....,. �.. ,- ._ .,_ - 'a --a•-- - - - { -tit , � I : I : : I _..... .:_. ; t : 1 -44 i , : , • i I I : � I` purl. y : I' i II I I , I..a ...i....-.__1._.I.... _.._t _....:.......:. _..:_ I I ....y...... j. r._�._r....}a t_.-i—�._y_.�...i _-h._l. f.._ l I �. i I I i r I i _1 r •r ' i I I I 1. 77) -0 ............. . V ' 3 0 Lq TPA 5.5� 2S. c2 1�.Fj2 a 4I o-# `qB. 5, y.3$ N ,Lldi g,�3 0.6 S.8(, ' 36 (o l.at ��ol Z,aST �-t.�41 s,zI dtP o, �. 7.19 8,�1"1 /a- IQ S.Zq g,�r3 +1 D 5 ( 6 — l 140 DSI 0f 8n+i 1 ho 1o3 "i�-'IR 0+ b0 © 4- 17,5 Tr Z of-L43 a t q?,S q qI 5 off- �3.5 4 + 5 (i V f jgg 01- G. 0 G � (,5 04 71 U + $Z Off' 9 o+9b G +A-7 4-00 +A I f:r S vq- H-1I R S-S3 I'2 .6 LA G.iZ c�z3 7,33 -7,oz cu? A eau-f G . 3 7 1.�9 s`I3 4.17 b S Q BS 67LEV 1 o L! 1--1, 05 TRH �f .�1 �.,� 1'`i•� BMx221 z,9v 27.0(o TPA, Qw-, '-7im: APR-14-2003 13:31 CITY OF RENTON PBPW 425 430 7241 P.01i17 TO: City of Renton PLANNING/BUILDING/ RECEIVED : �Oject PUBLIC WORKS DEPARTMENT APR 14 2003 ile Code #: Utility Systems - Fifth Floor R.W. BECK 1055 South Grady Way pY SEATTLE. WA Renton, WA 98055 �Q Date: 4/14/2003 �,C,l0A Mary Weber R.W. Beck Phone: Fax Phone: (206) 695-4 49-, }tom Lt-77Z I FROM: Allen Quynn Phone: (425) 430-7247 Fax Phone: (425) 430-7241 SUBJECT Springbrook Creek Number of pages including cover sheet 17 Floodplain Map Update REMARKS: ❑ Original to ❑ Urgent ❑ Reply ❑ Please ® For your be mailed ASAP Comment review Mary: Attached please find the City monuments and benchmarks for the valley area. Pleasc note that some of the benchmarks include only vertical information and others include' have any questions. just the horizontal. Let me know if you Go ahead and proceed with the surveying. You are probably right, Baker will just differ to us to make the call. Thanks_ APR-14-2003 13:32 CITY OF RENTON PBPW 425 430 7241 P.02/17 1917 1 SW 4 3 rd !�,l 197a, 59 C\ CITY OF RENTON SURVEY CONTROL NETWORK MONUMENTS & BR4CHMARKS CQ�mr 11 '1, 2 -N 757 41 A St, LEGEND till 0 Hor4m*d & Verfical 2222 Ho kwM Orgy 3333 0 vw6cd crjy loam— Ranson Oty Ur*s I z 36 -T23N 2.4E NE 1/4 APR-14-2003 13:32 CITY OF RENTON PBPW u L"- Mo aqp L7 425 430 7241 P.04i17 )i Ill =~f L 91 '7 i 1858 12 SW i.34th A 108 i / n • 36 T23N R4E N1 1/4 aTY OF RENTON CONTROLSURVEY NETWORK MONUMENTS & BD4CHMARKS M St. LEGEND 1111 ® Hcrizo a vw iooi 2222 Ord► 3333 -��� MOf1{�1lefti Itentm Clty Lkras H2 25 T23N R4E SE 1/4 13: s2 CITY OF RENTON PBPW I L CITY OF -RENTON SURM.. CONTROL NETWORK M oNUMff�rrs & BeqCHMAWS 9KCAL SERVICES MAMNOVe wom LEGEND llll ®HwUWW & vwt;cd 2222 a Hooff. 3 ®3 vwtied +" ' Moen 0 450 Saw ••w,� Rbffpn Coy Lknh 1:544W 25 T23N R4E H2 NE 1/4 Y ,Hrm-lg-eau,S 13:32 CITY OF RENTON PBPW a'- - Asa A"IT B-m aM t/7 425 430 7241 P.06/17 19TMR569WV4 CITY OF RENTON SURVEY CONTROL NETWORK MONUMENTS & BENCHMARKS Oqi KCAL SERVICES PLANN /sumvu4Q/pmlc woso QM4roo LEGEND 11ll ® Horiz ntd & Vwhcci 2222 IS Horiza*ci Only 3333 ® Vsrtkd Only 4r"J° Mawent O 450 9w — Rmron City Limit' � .sue 19 T23N R5E G3 NW 1/4 z oz r+rrc-i4-yes 13�33 CITY OF RENTON PBPW 425 430 7241 P.0?/1? CITY OF RENTON SURVEY CONTROL NETWORK MONUMENTS & BENCHMARKS TECHNICAL, SERVICES 0144100 LEGEND 1111 ® Hmkonfoi & Vw6cd 2222 e Nwizwci Orjy 3 ®3 Yof"Xi ® 900 --ow Renton city L,rn't! 1=5400 24 T23N R4E G2 NE 1/4 CITY OF RENTON PBPW aav - sa a09a19 8620 ovv Ary 425 430 7241 P.08i17 P -W I-A-M R51 EWW j/{ CITY OF RENTON SURVEY CONTROL I�ETy1,ORK MONUMENTS & BENCHMARKS TECHNICAL SERVICES QzrtMoo �+xa LEGEND 1111 ® hw4onw & VKtioal 2222 3333 ® Vwtiad Only ♦rl-o AAc►rnnwy 0 4SO -QW Renton City Units 1:5400 30 T23N R5E H3 NW 1/4 RPR-14-2003 13:33 CITY OF RENTON PBPW 425 430 7241 P.09i17 SECTION 19 T23N R5E W.M. 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1551 Location: Found 3/8" brass plug in a 10" monument case in centerline of Lind Ave SW at SW 23rd. St. (pipeline R.O.W.) Monument: 3/8 IN BRASS PLUG IN MON CASE NORTHING: 51992.882 FASTING: 395190.593 ELEVATION: 6.497 1856 Location: Found a Washington State Department of Transportation brass disk set in south shoulder of SR167, 1-405 overcrossing above the approximate centerline of SR167, Monument W.S.D.O.T. BRASS DISC NORTHING: 52927.573 EASTING: 395616.229 ELEVATION: 1896 Location: Found a 2" flat brass disc with a punch mark on a 4"x4" concrete post monument down 0.45' in a monument case at the constructed intersection of SW 16th Street & Lind Avenue SW. This mark is an alternate to the quarter comer to sections 24-23-4E & 19-23-5E. Monument 2 IN BRASS DISC W/PUNCH ON CONC MON, IN CASE, DN. 0.45' NORTHING. 52766.111 FASTING: 395209.265 ELEVATION: 7.834 G3-4 r+r-r[-14-�l1F� S 13: 33 CITY OF RENTON PBPW 425 430 7241 P.10i17 SECTION 30 T23N R5E WX 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1545 Location: Top of 2" brass disk set in concrete monument at intersection of E Valley Road and SW 27th Street. Monument BRASS DISC IN CONC MON INT E VALLEY RD & SW 27TH STREET NORTHING: FASTING: ELEVATION: 5.400 1551 Location: Found 3/8" brass plug in a 10" monument case in centerline of Lind Ave SW at SW 23rd. St. (pipeline R.O.W.) Monument 318 IN BRASS PLUG IN MON CASE NORTHING: 51992.882 FASTING' 395190.S93 ELEVATION: 9.497 1697 Location: Top of 2" brass disk set In concrete monument In centerline of Talbot Road 155' south of intersection of Talbot Road and South 27th Place. Monument BRASS DISC IN CONC MON CL TALBOT RD SO OF S 27TH PLACE NORTHING: 1699 EASTING: ELEVATION: 31.894 Location: Top of 1 3/4" brass disk in concrete monument in case in centerline of Talbot Road, opposite driveway to House No. 2819 Monument BRASS DISC IN CONC MON IN CASE CL TALBOT RD OPPOSITE HOUSE 2819 NORTHING: 51437.721 EASTING: 395997.313 ELEVATION: 30-278 H3-3 APR-14-2003 13:34 CITY OF RENTON PBPW 425 430 7241 P.11/17 SECTION 30 T23N R5E W.M. 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1916 Location: Top of copper plug set in concrete filled 3" pipe in WSDOT case in centerline of concrete walk on west side of Benson Rd. S., 250' north of intersection with S. 27th Place. Monument COPPER PLUG IN CONC FILLED PIPE WSDOT CASE NORTHING: EASTING: ELEVATION: 76.298 1925 Location: Top of N.E. Molt of traffic signal base S.E. quadrant of intersection of S.W. 3M Street and Lind Avenue S.W. Monument NE BOLT TRAFFIC SIGNAL BASE INT SW 39TH & LIND AVE SW NORTHING: EASTING: H3-5 ELEVATION: 6.2Q8 MrK-14-ebbs 13:34 CITY OF RENTON PBPW 425 430 7241 P.12i17 SECTION 30 T23N RSE WX 28 Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 230 NW Comer 29 T23N RSE Location: Found a copper tack in lead on a concrete post monument down 0.5' In a monument case at the constructed center of a cul-de-sac on the east end of S 23rd Street, west of Benson Drive SE, near the northeast comer of Teasdale Paris. See City of Renton monument reference card number 230. Monument LEAD PLUG 8 CU TK ON CONC MON, IN CASE, DN. 0.5' (MRG230) NORTHING: 51991.494 FASTING: 396406.222 ELEVATION: 70.334 1160 N 1/4 Corner 30 123N R5E Location: Found a 1/2" bronze button with a punch on a concrete post monument down 0.3' in a monument case approadmately 6' east of the constructed centerline of East Valley Highway at the northerly margin of an east -west pipeline right -of way. Another monument ( copper tack in lead on a concrete post moiround a ument down 1.0' in a monument case) exists approximately 6' west in the constructed centerline of East Valley Highway. Monument 1/2 1N BRONZE BUTTON W/ PUNCH ON CONC MON, IN CASE, DN. 0.3' NORTHING: 51991.935 EASTING: 395595.693 ELEVATION: 5.743 1161 NW Confer 30 T23N RSE Location: Found a 3" pipe 1.0' tall 900' west of Lind Ave SE on pipeline R.O.W. west from the extension of SW 23rd St_ on east side of creek Monument CAPPED 3 IN IRON PIPE WITH [x) NORTHING: 51993.586 EASTING: 394884.710 ELEVATION: h13-1 RPR-14-2003 13:34 CITY OF RENTON PBPW 425 430 7241 P.13i17 SECTION 26 T23N R4E WX 28-Apr-o0 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1161 NW Corner 30 T23N R5F, Location: Found a 3" pipe 1.0' tall 900' west of Lind Ave SE on pipeline R.O.W. west from the extension of SW 23rd St. on east side of creek. Monument: CAPPED 3 IN IRON PIPE MTH [Xj NORTHING: 61993.586 FASTING: 394884,710 ELEVATION: Location. Found a 2" brass disc on concrete post in a monument case at the center of a cul de sac on the north end of Oaksdale Ave SE. Monument: 2" BRASS DISC ON CONC MON. IN CASE NORTHING: 51267,437 FASTING: 394475.506 ELEVATION: 18" Location: Found a 2" flat brass disc with "X" stamped "Mullen 18913" on a 4'x4" concrete post monument down 0.W in a monument case at the constructed intersection of SW 3M Street & Raymonumentd Avenue SW. Monument 2 IN BRASS DISC WI [Xj ON CONC MON, IN CASE. DN 0.06' NORTHING: 50496.104 EASTING: 394836.553 ELEVATION: 5,540 H2-1 APR-14-2003 13:34 CITY OF RENTON PEPW 425 430 7241 P.14i17 SECTION 25 T23N R4E W.M. 2&Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 2108 Location: Found 2" Brass Disc with punch on a 4" x 4" concrete monument down 0.5' in a monument case at the intersection of SW 34th Street and Oaksdale Avenue SW. Monument 2 IN BRASS DISC W/PUNCH ON 4 INX4 IN CONC MON, IN CASE, DN. 0.5' NORTHING: 2109 EASTING: ELEVATION: 5.9s8 Location: Found a 1/2" brass plug with a punch mark on a 4"x4" concrete post monument down 0.5' in a monument case at the constructed intersection of SW 41st Street & Oaksdale Avenue SW. Monument 1/2 IN BRASS PLUG W/PUNCH ON CONC MON, IN CASE, DN. 0.5' NORTHING: 2182 EASTING. ELEVATION: 6.063 Location: Found a standard National Geodetic Survey (NGS) bench mark brass disc, NGS archive no. SY0610, stamped "E 460 1973" set in the top of the southeast corner of a 10'x20' concrete foundation for underground water mains and valves, approximately 98' northerly of a flagpole, approximately 52' westerly of the centerline of the southbound lanes of West Valley Highway, approximately 93' southerly of the north entrance road to NC Machinery Company, which is located at 17025 West Valley Highway, approximately 0.7 mile north of the constructed intersection of West Valley Highway & S 180th Street. Monument NGS DISC IN TOP OF CONC FNDN, STA E460 NORTHING: EASTING: ELEVATION: 8.928 H2-3 .... , _, l � �0 � i i Y Ut- RENTON PBPW 425 430 7241 P.17/17 SECTION 30 T23N R5E W.M. 28Apr-t70 Horizontal: NAD 1983191 Meters Vertical: NAVD 1988 Meters 1241. Location: Found Tack in Lead in Concrete -filled 21/2" iron pipe down 0.5' in a monument rase aPPM)dmately 200' south of the Intersection of SW41st Street and East Valley Road. Monument: TK IN LEAD IN CONC FILLED 2-1/2 IN I.P., IN CASE, 0N. 0.5' NORTHING: ELEVATION: 6.936 1494 FASTING: Location: Top of 1 314" brass disk in concrete monument In case in centerline of Talbot Road, opposite house No. 3023, W north of the centerline of S. 168th Street Monument: BRASS DISC IN CONC MON IN CASE NORTHING: 51172.894 FASTING: 396024.600 ELEVATION: 30.321 1522 Location: Top of 2" brass disk set in concrete monument at intersection of Talbot Road South and South 38th Court. Monument: BRASS DISC IN CONC MON INT TALBOT RD SANE) S 38TH CT NORTHING. ELEVATION: 28.gt 1544 EASTING: Location: Top of 2" brass disk set in cased Concrete monument at intersection of E. Valley Road and S.W. 34th StroeL Monument: BRASS DISC IN CASED CONC MON INT E VALLEY RD & SW 34TH STREET NORTHING: EASTING: ELEVATION: 6.022 H3-2 Tr'1TN 0 1 7 nrM-14-eQ0,.5 13: 35 CITY OF RENTON PBPW 425 430 7241 P.16i1? SECTION 30 T23N R5E WX 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1861 Location: Found a 3/8" brass plug and a punch mark on a 4"x4" concrete post monument down 0.3' in a monument case in the constructed centerfine of Lind Avenue SE approximately 30' north of the north building line of the Quality Classics building at 3000 East Valley Highway. This mark is an alternate to the center of 30-23ti5E. There is another monument with sirnilar description approximately 34' southerly on the constructed centerline of East Valley Highway. Monument: 3/8 IN BRASS PLUG W/PUNCH ON CONC MON, IN CASE, ON. 0.3' NORTHING: 51202.305 FASTING: 395168.555 ELEVATION: 6.0% 1862 Location: Found a copper plug with a punch mark on a 4'W" concrete post monument down 0.45' in a monument case at the constructed intersection of S 31 st Street & Smithers Court S. This monument is an alternate to the comer commonument to sections 29 & 30, T23N, R5E. Monument CU PLUG W/PUNCH ON CONC MON, IN CASE, DN. 0.45' NORTHING: 51223.575 FASTING: 3963OI A27 ELEVATION: 1864 Location: Found a 2" flat brass disc with "X" stamped "Mullen 18913" on a 4"x4" concrete post monument down 0.06' in a monument case at the constructed Intersection of SW 39th Street & Raymonumentd Avenue SW. Monument: 2 IN BRASS DISC W/ [X] ON CONC MON, IN CASE, ON 0.06' NORTHING: 50495.104 EASTING: 394836.553 ELEVATION: 5.940 H3-4 APR-14-2003 16:43 - - ---- ___ III I I �str. , rage 1 CITY OF RENTON PBPW 425 430 7241 P.01/02 28-Apr-00 Horiza 1903 Post -It* Fax Note Location: Found A 2" brass disc on concrete post in monument case at Intersection of East Valley Hwy. and S. 192nd St. and 80th Place S. Monument: 2" BRASS DOSC ON CONC. MON., IN MON. CASE NORTHING: 48939.884 EASTING: 394788.765 ELEVATION: ACTION COPY 1917 N 1/4 Corner 36 n3N R4E Location: Found brass plug in concrete approximately 1/4 mile west of Oaksdale Ave SW on R.R. tracks approx 1/2 mile south of SW 34 St Monument 1/2" BRASS DISC ON 4 IN X4 IN CONC MON NORTHING: 1973 FASTING: ELEVATION: 6.607 Location: Found 3" brass disk stamped "KC-F-12 1993" in sidewalk on the north side of S.W. 43rd Street (South 180th Street). Located south of two vaults located near the house at 7502 S.W, 43rd Street. Monument BRASS SURFACE DISC NORTHING: EASTING: ELEVATION: 7.805 2109 Location: Found a 1/2" brass plug with a punch mark on a 4"x4" concrete post monument down 0.5' in a monument case at the constructed intersection of SW 41st Street 3 Oaksdale Avenue SW. Monument 1/2 IN BRASS PLUG W/PUNCH ON CONC MON, IN CASE, ON. 0.5' NORTHING: EASTING: 12-2 ELEVATION: 6.063 APR-14-2003 13:32 CITY OF RENTON PBPW 425 430 7241 P.03i17 24 TIM ME Nz va ru • z5 T23N R4B NE 1/4 CITY OF RENTON SURVEY CONTROL NETWORK MONUMENTS & BENCHMARKS TECHNICAL SERVICES PLANNMMUUZD4G/pU8UC WORKS 0244/00 LEGEND 1111 Horizomd & Ver" 2222 ® Honzontd Only 3333 Vertical Orjy ♦r"-o Monwww t Renton Gty Linfh G 2 24 T23N ME SE 1/4 APR-14-2003 13:34 CITY OF RENTON PBPW 425 430 7241 P.15i17 SECTION 24 T23N R4E W.M. 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1854 Location: Found a 2" fiat brass disc with a punch mark on a 4' x4" concrete post monument down 0.7' in a monument case at the constructed intersection of SW 7th Street & Oaksdale Avenue SW. Monument: 2 IN BRASS DISC W/PUNCH ON CONC MON. IN CASE, DN. O.T NORTHING: 53517.345 E.ASTING: 394277.025 ELEVATION: 5.988 1881 Location: Set 3 112" brass disk stamped "City of Renton BM" in the top of the east end of the concrete railing on the north side of the S.W. 16th Street bridge over the P-1 Channel. Bridge is located just west of the intersection of S.W_ 16th Street and Oaksdale Avenue S.W. Monument BRASS DISC IN CONC. RAILING NORTHING: 52769.487 EASTING: 394515.946 ELEVATION: 7.363 1914 Location: Found a standard Coast & Geodetic Survey (CGS) bench mark brass disc, with no known National Geodetic Survey archive number, stamped "SS249 RESET 1984", set in the top of the most northwesterly concrete foundation of a steel transmission tower near the northwest comer of Longacres Race Track, approximately 90' southerly of the southerly edge of paving of the eastbound lanes of 1-405 and approximately 75' easterly of the easterly railroad tracks. Monument CGS DISC IN TOP OF CONC FNDN OF TOWER NORTHING: FASTING: ELEVATION: 6.798 G2-2 lnrrastr.; Page 2 APR-14-2003 16:43 CITY OF RENTON PBPW 425 430 7241 P.02/02 SECTION 19 T23N RSE W.M. 28-Apr-00 Horizontal: NAD 1983/91 Meters Vertical: NAVD 1988 Meters 1922 Location: Found brass disk on west sidewalk at the north end of the Lind Ave SW bridge over 1405 Monument: BRASS SURFACE DISC NORTHING: 2484 EASTING: ELEVATION: 15.400 Location: Top of 1/4" brass pin set in concrete filled 2" I.P. in a monument case 1.5' southeast of the constructed intersection of S. 21st Street and Talbot Road S. Monument BRASS PIN IN CONC FILLED I.P. IN CASE NORTHING: EASTING: ELEVATION: 62.176 11 G3-5 �"� NAVD88-3.58=NGVD29 STA BS HI F BM1973 0.58 25.027 RP1 RP2 RP3 BM1973 RP3 1.224 23.6 0 2.7 12 21 30 38 41 44 48 54 58 62 66 74 81 88 91 RP3 BM1973 RN RP4 RP5 BM 1973 1.821 23.786 -3.257 23.378 S ELEV ELEV NAVD88 NGVD29 25.607 22.027 -3.29 21.737 18.157 -3.378 21.649 18.069 -0.203 24.824 21.244 0.541 25.568 21.988 24.824 21.244 1.177 24.777 21.197 0.85 24.45 20.87 -3.511 20.089 16.509 -6.496 17.104 13.524 -7.946 15.654 12.074 -11.111 12.489 8.909 -13.293 10.307 6.727 -14.438 9.162 5.582 -14.772 8.828 5.248 -14.724 8.876 5.296 -14.184 9.416 5.836 -13.549 10.051 6.471 -11.724 11.876 8.296 -9.351 14.249 10.669 -6.222 17.378 13.798 -4.553 19.047 15.467 -4.251 19.349 15.769 1.222 24.822 21.242 25.607 22.027 -3.665 20.121 16.541 -3.58 -0.329 23.049 19.469 2.23 25.608 22.028 2092 Station Elev 0 18.92 22 11.42 50 10.92 60 10.452 62 8.42 85 8.32 97 8.42 118 16.42 166 18.92 Section 2077 ELEV ELEV STA BS HI FS NAVD88 NGVD29 RN -3.01 23.131 20.121 16.541 RP5 -0.21 22.921 19.341 0 0.947 24.078 20.498 11 0.402 23.533 19.953 30 -8.298 14.833 11.253 42 -9.155 13.976 10.396 50 -11.56 11.571 7.991 53 -13.05 10.081 6.501 58 -14.23 8.901 5.321 62 -15.14 7.991 4.411 65 -15.28 7.851 4.271 69 -14.47 8.661 5.081 71 -13.02 10.111 6.531 73 -9.54 13.591 10.011 79 -6.77 16.361 12.781 90 -1.7 21.431 17.851 99 -0.754 22.377 18.797 RP5 -0.23 22.901 19.321 RN -2.99 20.141 16.561 FEQ 2077 Station Elev 0 18.92 24 10.92 34 10.42 44 6.62 54 6.52 66 6.42 92 18.92 Station 9010 ELEV ELEV STA BS HI FS NAVD88 NGVD29 BM1881 1.88 26.037 24.157 20.577 0 4.23 21.807 18.227 10 8.49 17.547 13.967 19 8.98 17.057 13.477 26 9.8 16.237 12.657 27.3 9.99 16.047 12.467 27.4 12.91 13.127 9.547 39 14.83 11.207 7.627 57 depth 17.4 8.637 5.057 59.5 0 18.38 7.657 4.077 62.5 1.6 19.98 6.057 2.477 67.5 3.9 22.28 3.757 0.177 71.5 5.8 24:18 1.857 -1.723 75.5 5.3 23.68 2.357 -1.223 79.5 4.2 22.58 3.457 -0.123 82.5 2.6 20.98 5.057 1.477 84.5 1.5 19.88 6.157 2.577 88 0 18.41 7.627 4.047 95 17.16 8.877 5.297 109.5 15.82 10.217 6.637 109.6 0.22 25.817 22.237 BM1881 1.86 24.177 20.597 Station 9010 Station Survey 20C FEQ 9007 FEQ 0 18.227 10 13.967 19 13.477 26 12.657 27.3 12.467 27.4 9.547 39 7.627 57 5.057 9010 Station Elev 110.94 15.44 118.48 14.81 125.05 12.48 136.54 12.78 138.45 14.06 140.93 12.99 143.31 9.64 146.87 6.38 150.33 4.3 160.963 3.35 168.48 3.88 169.6 7.43 176.12 10.77 193.44 11.58 195.86 10.52 209.95 10.4 213.44 12.2 224.04 12.44 DWI Section 9007 (Approximatley 40' d/s of Oaksdale bridge) 59.5 62.5 67.5 71.5 75.5 79.5 82.5 84.5 88 95 109.5 109.6 0 17 29 29 48 54.5 66.5 73 95 110 150 -10 -7 -4 0 3 6 20 25 30 35 40 46 52 57 64 74 84 93 99 105 108 108.1 4.077 2.477 0.177 -1.723 -1.223 -0.123 1.477 2.577 4.047 5.297 6.637 22.237 15.1 15.2 13.3 9.3 4.3 1.5 1.5 4 13 17 17.5 25 20 = 15 ° 10 w > 5 0 w 0 9 -50 18 -20 17 -17 16 -14 15 -10 14 -7 13 -4 12 10 11 15 10 20 9 25 8 30 7 36 6 42 5 47 4 54 1.5 64 1.5 74 4 83 5 89 6 95 6.5 98 17 98.1 50 150 Station (ft) z -�- Survey 2003 -� - FEQ Cross section 9007 Station Elevation 0 15.1 17 15.2 29 13.3 29 9.3 48 4.3 54.5 1.5 66.5 1.5 73 4 95 13 110 17 150 17.5 2072 STA BS HI FS BM1881 4.525 -19.632 RP8 RP9 RP9 -2.192 19.794 RP8 BM1881 ... 0 10 16 24 27 31 35 39 43 47 51 53 54.5 68 86 108 116 135 6.29 23.892 1.4 2.1 2.6 2.7 2.4 2.3 1.6 1.4 2072 ELEV ELEV NAVD88 NGVD29 24.157 20.577 -3.293 16.339 12.759 -2.03 17.602 14.022 -3.398 16.396 12.816 4.413 24.207 20.627 17.602 14.022 7.3 16.592 13.012 7.49 16.402 12.822 7.87 16.022 12.442 16.83 7.062 3.482 18.23 5.662 2.082 18.93 4.962 1.382 19.43 4.462 0.882 19.53 4.362 0.782 19.23 4.662 1.082 19.13 4.762 1.182 18.43 5.462 1.882 18.23 5.662 2.082 16.79 7.102 3.522 14.62 9.272 5.692 15.01 8.882 5.302 7.14 16.752 13.172 5.45 18.442 14.862 4.05 19.842 16.262 18- 16 - - - 14 - -- -- 00 12 - -- - -- - 00 18 - -Series I a Z 6 --` - =-= - ----= 4 - - -- -- --- - 2 --- -- _ - 0 0 �o 00 2072 Station Elev 0 16 23 8.33 35 8.33 50 3.33 56 1.33 70 1.33 70.7 1.1 85.3 1.1 86 1.33 116 1.33 122 3.33 160 16 Station 2074 ELEV STA BS HI FS NAVD88 RP8 8.59 24.929 16.339 12.759 pk nail on curb, east end of oaksdale RP9 7.36 17.569 13.989 sw corner of inlet on north side of overpass 24.929 21.349 0 5.05 19.879 16.299 12 5.3 19.629 16.049 18 5.75 19.179 15.599 24 6.27 18.659 15.079 38 12.39 12.539 8.959 50 17.65 7.279 3.699 left edge of water 67 17.65 7.279 3.699 right edge of water 75 15.75 9.179 5.599 84 15.25 9.679 6.099 101 3.88 21.049 17.469 depth 51 1.5 5.779 2.199 53 1.6 5.679 2.099 55 2.2 5.079 1.499 58 2.7 4.579 0.999 60 2.1 5.179 1.599 63 1 6.279 2.699 66 1 6.279 2.699 Section 1010 (approximately 40' d/s of 1-405) 25 20 0 15 10 m 0 50 100 150 Station (ft) -0 Survey 2003 -�- FEQ ELEV A&E Survey STA Survey 20( FEQ section 1010 FEQ 0 16.299 #N/A 12.719 12 16.049 #N/A 12.469 18 15.599 #N/A 12.019 24 15.079 #N/A 11.499 38 8.959 - #N/A 5.379 50 3.699 #N/A 0.119 ( 51 2.199 #N/A -1.381 2073 Station Elev 0 16 45 16 45.1 2 55 2 58 1 72 1 75 2 108.9 2 109 16 189 16 left edge of water 53 2.099 #N/A -1.481 55 1.499 #N/A -2.081 58 0.999 #N/A -2.581 60 1.599 #N/A -1.981 63 2.699 #N/A -0.881 66 2.699 #N/A -0.881 67 3.699 #N/A 0.119 75 5.599 #N/A 2.019 84 6.099 #N/A 2.519 101 17.47 #N/A 13.89 right edge of water Station 2063 ELEV STA BS HI FS NAVD88 NGVD29 BM1854 -0.7 20.346 19.646 16.066 RP10 -1.232 19.114 15.534 -1.131 20.245 RP11 -1.304 18.941 15.361 BM1854 -0.647 19.598 16.018 RP10 7.09 26.204 19.114 15.534 7.25 18.954 15.374 -3.58 0 13.37 12.834 9.254 10 13.66 12.544 8.964 15 14.64 11.564 7.984 31 18.51 7.694 4.114 50 19.94 6.264 2.684 56 0.8 5.489 1.909 65 1.4 4.889 1.309 71 1.4 4.889 1.309 76 1.3 4.989 1.409 82 1.3 4.989 1.409 87 1.2 5.089 1.509 90 19.89 6.314 2.734 93 19.14 7.064 3.484 104 14.31 11.894 8.314 123 10.47 15.734 12.154 135 5.89 20.314 16.734 148 5.26 20.944 17.364 -7 13.54 12.664 9.084 -27 3.55 22.654 19.074 RP 10 7.06 19.144 15.564 RP11 7.22 18.984 15.404 Section 2063 (Approximately 2000 feet d/s of Grady Way) 25 20 c 15 10 5 w r, 0 100 200 Station (ft) -+-Survey 2003 -f- FEQ 2063 Station Elev 0 16.9 25 8.6 43 8.6 58 3.6 68.2 0.2 79.8 0.2 84 1.6 124 1.6 130 3.6 154 11.6 SPRINGBROOK CREEK X-S DSO 1 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0.0 12.05 10.4 11.86 15.0 11.07 28.0 7.47 33.0 6.57 36.0 5.74 40.0 4.68 44.0 3.73 47.0 2.97 50.0 3.47 53.0 3.86 54.0 4.19 54.5 5.76 61.0 6.82 81.0 6.52 88.0 7.51 98.0 11.46 109.0 15.31 115.0 16.12 123.0 16.41 18.00 16.00 14.00 12.00 Z 10.00 a - w 6.00 4.00 2.00 Springbrook Creek DSO 1 123.0 109.0 ,r 15. 8.0 28.0 33.0 88.0 .0 1 40.0 44. 0 0. 47.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 OFFSET SPRINGBROOK CREEK X-S DSO 2 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0.0 12.24 10.0 12.06 22.0 12.18 26.0 11.00 34.0 7.98 39.0 6.71 40.0 5.88 41.0 5.38 46.0 4.93 50.0 3.91 55.0 2.95 59.0 2.84 64.0 3.48 67.0 5.88 74.0 7.24 92.0 6.92 100.0 8.36 112.0 12.64 127.0 16.58 132.0 17.17 SPRINGBROOK CREEK X-S DSO 1 RAW DATA STA BS HI FS ELEV TPF 5.76 17.56 11.80 0+00.0 5.51 12.05 0+10.4 5.70 11.86 0+15.0 6.49 11.07 0+28.0 10.09 7.47 0+33.0 10.99 � ' 0+36.0 11.82 5.74 0+40.0 1.06 4.68 0+44.0 2.01 3.73 0+47.0 2.77 2.97 0+50.0 2.27 3.47 0+53.0 1.88 3.86 0+54.0 1.55 4.19 0+54.5 11.80 5.76 0+61.0 10.74 6.82 0+81.0 11.04 6.52 0+88.0 10.05 7.51 0+98.0 6.10 11.46 1+09.0 2.25 15.31 1+15.0 1.44 16.12 1 +23.0 1.15 16.41 0-7.5 5.07 12.49 TPF 5.76 11.80 SPRINGBROOK CREEK X-S DSO 2 RAW DATA STA BS HI FS ELEV TPF 5.92 17.72 11.80 0+00.0 5.48 12.24 0+10.0 5.66 12.06 0+22.0 5.54 12.18 0+26.0 6.72 11.00 0+34.0 9.74 7.98 0+39.0 11.01 6.71 0+40.0 11.84 5.88 0+41.0 0.50 5.38 0+46.0 0.95 4.93 0+50.0 1.97 3.91 0+55.0 2.93 2.95 0+59.0 3.04 2.84 0+64.0 2.40 3.48 0+67.0 11.84 5.88 0+74.0 10.48 7.24 0+92.0 10.80 6.92 1 +00.0 9.36 8.36 1 +12.0 5.08 12.64 1+27.0 1.14 16.58 1 +32.0 0.55 17.17 TPF 5.93 11.79 20.00 18.00 16.00 14.00 Z 12.00 4.00 2.00 0.00 26.0 Springbrook Creek DSO 2 64.0 100.0 112.0 ► 132.0 0 0.0 20.0 40.0 60.0 80.0 100.0 120.0 140.0 OFFSET SPRINGBROOK CREEK X-S USO 1 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 13.36 4 12.5 8 12.73 18.5 12.54 22.3 11.67 28 9.74 32 8.22 38.8 7.3 39 5.82 40 5.32 42 5.02 46 4.05 48 3.81 51.5 3.76 54.5 4.42 55.2 5.24 55.5 5.82 56 6.62 67 7.03 77 7.04 89 6.78 95 7.06 101 6.93 104 7.45 110 8.73 SPRINGBROOK CREEK X-S USO 1 RAW DATA STA BS HI TPE 5.29 18.08 0-9.5 0+00.0 0+04.0 0+08.0 0+18.5 0+22.3 0+28.0 0+32.0 0+38.8 0+39.0 0+40.0 0+42.0 0+46.0 0+48.0 0+51.5 0+54.5 0+55.2 0+55.5 0+56.0 0+67.0 0+77.0 0+89.0 0+95.0 1 +01.0 1 +04.0 1+10.0 TPE 0.50 0.80 1.77 2.01 2.06 1.40 0.58 FS ELEV 12.79 0.33 17.75 4.72 13.36 5.58 12.50 5.35 12.73 5.54 12.54 6.41 11.67 8.34 9.74 9.86 8.22 10.78 7.30 12.26 5.82 5.32 5.02 4.05 3.81 3.76 4.42 5.24 12.26 5.82 11.46 6.62 11.05 7.03 11.04 7.04 11.3 6.78 11.02 7.06 11.15 6.93 10.63 7.45 9.35 8.73 5.30 12.78 16 14 12 10 Z O 8 W J W 6 4- 2- Springbrook Creek USO 1 0 8.5 22.3 28 32 110 8.8 104 101 40 42 55.2 J54 5 51.5 20 40 60 OFFSET 100 120 SPRINGBROOK CREEK X-S US7-1 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 20.59 7 18.69 16 16.25 22 14.2 27 13.13 31.9 13.28 33.8 13.29 43.4 13.17 48 11.83 68 6.34 72 6.2 78 5.6 85 5.4 94 5.2 102 5.05 109 5.49 116 5.6 122 6.2 131 7.67 144 11.67 SPRINGBROOK CREEK X-S US7-1 RAW DATA STA BS HI FS ELEV TPD 6.18 18.89 12.71 0+00.0 � u51 59' 0+07.0 0.2 18.69 0+16.0 2.64 16.25 0+22.0 4.69 14.2 0+27.0 5.76 13.13 0+31.9 5.61 13.28 0+33.8 5.6 13.29 0+43.4 5.72 13.17 0+48.0 7.06 11.83 0+68.0 12.55 6.34 0+72.0 12.69 6.2 0+78.0 0.6 5.6 0+85.0 0.8 5.4 0+94.0 1 5.2 1 +02.0 1.15 5.05 1 +09.0 0.71 5.49 1 +16.0 0.6 5.6 1+22.0 12.69 6.2 1 +31.0 11.22 7.67 1 +44.0 7.22 11.67 TPD 6.18 12.71 Springbrook Creek US7-1 0 1s 22 43.4 48 144 331 2 122 1 0 20 40 60 80 100 120 OFFSET 140 160 SPRINGBROOK CREEK X-S DSG-1 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 14.14 4.5 12.55 8.6 12.58 18.8 12.46 22 12.19 31 9.21 38 7.74 43 6.3 46 5.5 48 5.3 52 5.4 55 6.3 58 7.66 69 7.88 77 7.74 77.8 6.34 77.9 5.86 81.5 4.44 86 3.46 90 3.26 93 4.69 97 5.46 101 5.54 102.5 5.66 103 6.3 108 7.81 113 8.69 111.5 9.29 SPRINGBROOK CREEK X-S DSG-1 Raw Data STA BS HI FS ELEV TPC 3.52 17.19 13.67 0+00.0 3.05 14.14 0+04.5 4.64 12.55 0+08.6 4.61 12.58 0+18.8 4.73 12.46 0+22.0 5 12.19 0+31.0 7.98 9.21 0+38.0 9.45 7.74 0+43.0 10.89 6.3 0+46.0 0.8 5.5 0+48.0 1 5.3 0+52.0 0.9 5.4 0+55.0 10.89 6.3 0+58.0 9.53 7.66 0+69.0 9.31 7.88 0+77.0 9.45 7.74 0+77.8 10.85 6.34 0+77.9 0.48 5.86 0+81.5 1.9 4.44 0+86.0 2.88 3.46 0+90.0 3.08 3.26 0+93.0 1.65 4.69 0+97.0 0.88 5.46 1 +01.0 0.8 5.54 1 +02.5 0.68 5.66 1 +03.0 10.89 6.3 1 +08.0 9.38 7.81 1 +13.0 8.5 8.69 1 +11.5 7.9 9.29 TPC 3.52 13.67 16 14 12 10 Z O F- 8 W J W 6 4 2 0 Springbrook Creek DSG-1 8 822 31 111. 113 8 43 55 7 77.8 003 52 81.5 93 01�02.5 90 0 20 40 60 80 100 120 OFFSET SPRINGBROOK CREEK X-S US7-2 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 13.94 6 12.2 9 12.72 11 12.69 21 12.33 25 11.49 38.5 7.47 50 6.26 55 4.74 60 5.16 64 5.66 70 5.31 75 5.35 81 4.93 88 5.66 97 6.26 104 7.07 112 8.74 121 11.73 130 14.66 147 20.19 SPRINGBROOK CREEK X-S US7-2 RAW DATA STA BS HI FS ELEV TPD 4.86 17.57 12.71 0+00.0 3.63 13.94 0+06.0 5.37 12.20 0+09.0 4.85 12.72 0+11.0 4.88 12.69 0+21.0 5.24 12.33 0+25.0 6.08 11.49 0+38.5 10.1 7.47 0+50.0 11.31 6.26 0+55.0 1.52 4.74 0+60.0 1.1 5.16 0+64.0 0.6 5.66 0+70.0 0.95 5.31 0+75.0 0.91 5.35 0+81.0 1.33 4.93 0+88.0 0.6 5.66 0+97.0 11.31 6.26 1+04.0 10.5 7.07 1 +12.0 8.83 8.74 1 +21.0 5.84 11.73 1 +30.0 2.91 14.66 1 +47.0 � Pk TPD 4.87 12.70 25 20 Z 15 O H W J w 10 Springbrook Creek US7-2 6147 0 g 21 25 130 Z121 8.5 50 112 104 20 40 60 80 100 120 140 160 OFFSET SPRINGBROOK CREEK X-S # DS16-1 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 19.79 4 19.82 15.5 19.14 20 18.84 33 13.3 41 8.26 44 8.07 48 8.6 58 9.84 65 8.73 68 8.36 70 7.02 72 6.52 75 6.01 78 4.97 80 4.94 84 5.22 86 6.19 87 7.03 88 7.75 100 8.47 109 8.97 119 8.93 120 7.09 122 6.76 124 6.68 127 6.21 128 6.11 128.01 17.41 SPRINGBROOK CREEK X-S # DS16-1 RAW DATA STA BS HI FS ELEV TPA 5.5 25.02 19.52 TP1 12.85 12.17 TP1 2.05 14.22 12.17 0+33.0 0.92 13.3 0+41.0 5.96 8.26 0+44.0 6.15 8.07 0+48.0 5.62 8.6 0+58.0 4.38 9.84 0+65.0 5.49 8.73 0+68.0 5.86 8.36 0+70.0 7.2 7.02 0+72.0 0.5 6.52 0+75.0 1.01 6.01 0+78.0 2.05 4.97 0+80.0 2.08 4.94 0+84.0 1.8 5.22 0+86.0 0.83 6.19 0+87.0 7.19 7.03 0+88.0 6.47 7.75 1 +00.0 5.75 8.47 1+09.0 5.25 8.97 1 +19.0 5.29 8.93 1 +20.0 7.13 7.09 1 +22.0 0.33 6.76 1 +24.0 0.41 6.68 1+27.0 0.88 6.21 1 +28.0 0.98 6.11 TP1 2.04 12.18 TP1 12.76 24.94 0+20.0 6.1 18.84 0+15.5 5.8 19.14 0+04.0 5.12 19.82 0-3 5.41 19.53 0+00.0 5.15 19.79 TPA 5.41 19.53 25 20 Springbrook Creek DS16-1 20 128.01 33 8 4 68 7072 75 87 86 119 2 �2 0 20 40 60 80 100 120 140 OFFSET SPRINGBROOK CREEK X-S DS16-2 FEQXLST TABLE#= 1000 OUT12 EXTEND STATION = 0. NAVM=O SCALE=1.0 NSUB 3 0.09 0.04 # OFFSET ELEVATION SUB 0 19.6 7.7 19.75 17.5 19.5 22 18.56 28 16.53 35 12.05 43 8.23 43.5 7.02 44.5 6.64 47.5 6.37 51 5.93 53.5 5.24 56 4.97 58 5.81 60 7.02 65 8.59 77 8.74 87 8.71 94 8.66 96 7.1 97 6.65 100 6.43 102 6.39 104 6.28 104 17.28 SPRINGBROOK CREEK X-S DS16-2 RAW DATA STA TPA 0+00.0 0+07.7 0+17.5 0+22.0 0+28.0 0+35.0 TP2 TP2 0+43.0 0+43.5 0+44.5 0+47.5 0+51.0 0+53.5 0+56.0 0+58.0 0+60.0 0+65.0 0+77.0 0+87.0 0+94.0 0+96.0 0+97.0 1 +00.0 1 +02.0 1 +04.0 1 +04.0 TP2 TP2 TPA BS HI FS ELEV 4.57 24.09 19.52 4.49 19.6 4.34 19.75 4.59 19.5 5.53 18.56 7.56 16.53 12.04 12.05 13.78 10.31 4.04 14.35 6.12 8.23 7.33 7.02 0.38 6.64 0.65 6.37 1.09 5.93 1.78 5.24 2.05 4.97 1.21 5.81 7.33 7.02 5.76 8.59 5.61 8.74 5.64 8.71 5.69 8.66 7.25 0.45 6.65 0.67 6.43 0.71 6.39 0.82 6 28w 17.28 14.05 24.36 4.04 10.31 4.87 19.49 BM1881 2.9 27.06 24.16 TPA 7.56 19.5 BM1881 2.9 24.16 Springbrook Creek DS16-2 1 .5 104 N2835 43 94 4 5 7.5 60 9 51 8 a 04 0 20 40 60 80 100 120 OFFSET C� APPENDIX C DIGITAL APPENDIX This appendix includes the digital materials on CD included in the enclosed CD holder. Included are three folders containing the following materials. Also provided below is a narrative describing the detailed modeling files. \Flood Profiles \Floodplain Map (includes floodway) \FEMA Within the FEMA folder, the FEQ input and output files necessary to run the model are included. The files are organized in the following subdirectories. \EXIST — This subdirectory contains the flow input files generated by HSPF for the various storm events. \FEQ — This subdirectory contains the FEQ models and the FEQ output. \FEQUTL — This subdirectory contains the FEQUTL tables that were developed to define channel cross sections, culvert crossings, bridges and special flow conditions that are used as input into the FEQ model. Below is a discussion of the files found in each of the directories: \EXIST The FEQ input files containing the flow from each subbasin include: File Name HSPF Subbasin MILL 51 SPRING 33 PANTHER 107 ROLLING 103 SBP4 101 SBS5 31 SBS6 29 SBS7A 27 SBS7B 23b SBS8 25 SBS9A 15 SBS9B 21 SBS9C 23a SBS10 17 SBS11 19 SBS12 13 SBS13 11 SBS14 7 SBS 15 9 SBS16 2 SBS 171 5+43 These tables are located in subdirectories according to the return period and flow regime (Conveyance or Storage) they represent. For example, the files for the 25-year event based on conveyance criteria are located in the \EXIST\25c\ subdirectory. \FEQ The files contained in this directory are either FEQ model input files or output files. Input files are of the form: FEQINX_YY.605 Output files are of the form: 605X_YY.out Where, X is either C indicating a conveyance event or S indicating a storage event. YY indicates either the storm return period (2 for 2-year, 10 for 10-year, etc.) or FW indicating that it is a floodway simulation. \FEQUTL The files in this directory are defined in the accompanying index. To run FEQ, start in the FEMA directory and type in: FEQ FEQINX_YY.605 OUTPUT Where, FEQINX_YY.605 is defined as shown above and OUTPUT is the FEQ output file. FEQINX_YY.605references all the FEQ input tables and they must be in the right directory ff EMA\FEQUTL) for it to work. City of Renton Springbrook Creek FEMA Remapping Study November. 2005 Tabular Summmary of FEQ-Referenced Tables FEQ Table Number Desch tion Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 2061 PSFORBYU PSFORBYI Cross section xtabs.spg HEC.SPG S rin 2.da1 2060 Cross section xtabs.spg HEC.SPG S rin 2.dat S rin 2.dat S rin 2.dat S rin 2.dat S rin 2.dat 2059 PSF6RBY2 Cross section Cross section xtabs.spg xtabs.spg HEC.SPG HEC.SPG 2058 PSF6RBY3 _ _ 2057 PSFORBY4 Cross section Cross section xtabs.spg xtabs.spg HEC.SPG HEC.SPG 2056 PSFORBYS 2055 PSFORBY6 Cross section xtabs.spg HEC.SPG S rin 2.dat 2054 PSF6RBY7 Cross section xtabs.spg HEC.SPG S rin 2.dat S rin 2.dat 2053 PSFORBYB Cross section xtabs.spg HEC.SPG 2052 PSFORBY9 Cross section xtabs.spg HEC.SPG S rin 2.dat S rin 2.dat S rin 2.dat S rin 2.dat none none none none none none 2051 PSFORBIO Cross section xtabs.spg HEC.SPG 2050 PSFORBYD Cross section xtabs.spg HEC.SPG 4012 SBRKAU Cross section xtabs.703 HEC.SPG 4010 SBRKAD Cross section xtabs.703 XTABIN.703 1055 S16PIPU Cross section xtabsa UP.ext XTABSA.IN 1055 S16PIPD Cross section xtabsa UP.ext XTABSA.IN 1068 S17PIPU Cross section xtabsa UP.ext XTABSA.IN 1088 S17PIPD Cross section xtabsa UP.ext XTABSA.IN 4015 SBRKBU Cross section xtabs.703 XTABIN.703 4014 SBRKBI Cross section xtabs.703 XTABIN.703 none 4012 SBRKBD Cross section xtabs.703 XTABIN.703 none none none 2074 SBRKCU Cross section xtabs.soo XTABIN.703 4020 SBRKC4 Cross section xtabs.703 XTABIN.703 4019 SBRKC3 Cross section xtabs.703 XTABIN.703 none 4018 SBRKC2 Cross section xtabs.703 XTABIN.703 none 4016 SBRKCI Cross section xtabs.703 XTABIN.703 none 4015 SBRKCD Cross section xtabs.703 XTABIN.703 none 4022 SBRKOU Cross section xtabs.703 XTABIN.703 none 4021 SBRKAI Cross section xtabs.703 XTABIN.703 none 4028 SBRKDD Cross section xtabs.703 XTABIN.703 none 4025 SBRKEU Cross section xtabs.703 XTABIN.703 none 4022 SBRKED Cross section xtabs.703 XTABIN.703 none 1057 S15PIPU Cross section xtabsa UP.ext XTABSA.IN none 1057 S15PIPD Cross section xtabsa UP.ext XTABSA.IN none 4027 SBRKFU Cross section xtabs.703 XTABIN.703 none 4027 SBRKFD Cross section xtabs.703 XTABIN.703 none 9021 SBRKGU Cross section xtabs2.ex XTABINe2.txt none 9014 SBRKGI Cross section xtabs2.ex XTABINe2.txt none 9012 OAKBRU Cross section xtabs2.ex XTABINe2.bd none 9010 OAKBRD Cross section xtabs2.ex XTABINe2.txt none 9005 SBRKG2 Cross section xtabs.y2k XTABIN.Y2K none 9004 SBRKG3 Cross section xtabs.y2k XTABIN.Y2K none 9004 SBRKGD Cross section xtabs.y2k XTABIN.Y2K none 1058 S14PIPU Cross section xtabsa UP.ext XTABSA.IN none 1058 S14PIPD Cross section xtabsa UP.ext XTABSA.IN none 1059 FS11PIPU Cross section xtabsa UP.ext XTABSA.IN none 1059 FS11PIPD Cross section xtabsa UP.ext XTABSA.IN none 9035 SBRKHU Cross section xtabs2.ex XTABINe2.txt none 9033 SBRKH6 _ Cross section x1abs2.ex XTABINe2.txt none 9032 SBRKHS Cross section xtabs2.ex XTABINe2.txt none Page 1 of 9 FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 9031 SBRKH4 Cross section xtabs2.ex XTABINe2.txt none 9030 SBRKH3 Cross section xtabs2.ex XTABINe2.bd none 9029 SBRKH2 Cross section xtabs2.ex XTABINe2.txt none none 9021 SBRKHD Cross section xtabs2.ex XTABINe2.txt 9055 SBRKJU Cross section xtabs2.ex XTABINe2.txt none none none 9053 SBRK15 Cross section xtabs2.ex XTABINe2.txt 9052 SBRKI4 Cross section xtabs2.ex XTABINe2.txt 9043 HDBRID Cross section xtabs2.ex XTABINe2.bct none none none 9040 SBRKI3 Cross section xtabs2.ex XTABINe2.txt 9039 SBRK12 Cross section xtabs2.ex XTABINe2.txt 9036 SBRKII Cross section xtabs2.ex XTABINe2.txt none 9035 SBRKHD Cross section xtabs2.ex XTABINe2.bd none 1060 S12PIPU Cross section xtabsa UP.ext XTABSA.IN none 1060 S12PIPD Cross section xtabsa UP.ext XTABSA.IN none 9073 SBRKJU Cross section xtabs2.ex XTABINe2.txt none 9071 SBRKJ5 Cross section xtabs2.ex XTABINe2.bd none 9069 SBRKJ4 Cross sect(on xtabs2.ex XTABINe2.bd none 9065 SBRKJ3 Cross section xtabs2.ex XTABINe2.bd none 9058 SBRKJ2 Cross section xtabs2.ex XTABINe2.txt _ none 9056 SBRKJI Cross section xtabs2.ex XTABINe2.bd none 9055 SBRKJD Cross section xtabs2.ex XTABINe2.bd none 9078 SBRKKU Cross section xtabs2.ex XTABINe2.bd none 9075 SBRKKI Cross section xtabs2.ex XTABINe2.txt none 9073 SBRKKD Cross section xtabs2.ex XTABINe2.txt none 9079 SBRKLU Cross section xtabs2.ex XTABINe2.txt none 9078 SBRKHD Cross section xtabs2.ex XTABINe2.bd none 9080 ISBRKMU Cross section xtabs2.ex XTABINe2.txt none 9080 SBRKMI Cross section xtabs2.ex XTABINe2.txt none 9082 SBRKMD Cross section xtabs2.ex XTABINe2.txt none 9102 SBRKNU Cross section xtabs2.301 XTABIN2.301 none 9102 SBRKND Cross section xtabs2.301 XTABIN2.301 none 9105 SBRKOU Cross section xtabs2.301 XTABIN2.301 none 9104 SBRKOI Cross section xtabs2.301 XTABIN2.301 none 9103 SBRKO2 Cross section xtabs2.301 XTABIN2.301 none 9102 SBRKOD Cross section xtabs2.301 XTABIN2.301 none 9106 SBRKPU Cross section xtabs2.301 XTABIN2.301 none 9105 SBRKPD Cross section xtabs2.301 XTABIN2.301 none 9107 SBRKQU Cross section xtabs2.301 XTABIN2.301 none 9106 SBRKQD Cross section xtabs2.301 XTABIN2.301 none 9107 SW34TH Cross section xtabs2.301 XTABIN2.301 none 9107 SBRKRD Cross section xtabs2.301 XTABIN2.301 none 9110 SBRKJU Cross section xtabs2.301 XTABIN2.301 none 9109 SBRKSI Cross section xtabs2.301 XTABIN2.301 none 9108 SW34TH Cross section xtabs2.301 XTABIN2.301 none 9112 SBRKTU Cross section xtabs2.301 XTABIN2.301 none 9111 SBRKTI Cross section xtabs2.301 XTABIN2.301 none 9110 SBRKTD Cross section xtabs2.301 XTABIN2.301 none 1063 S6PIPU Cross section xtabsa UP.ext XTABSA.IN none 1063 S6PIPD Cross section xtabsa UP.ext XTABSA.IN none 9114 SW41ST Cross section xtabs2.301 XTABIN2.301 none 9115 SBRKUD Cross section xtabs2.301 XTABIN2.301 none 2085 SBRKVU Cross section xtabs2.oak XTABIN2.oak none 2083 SBRKV7 Cross section xtabs2.oak XTABIN2.oak none 2082 SBRKV6 Cross section xtabs2.oak XTABIN2.oak none 2081 SBRKVS Cross section xtabs2.oak XTABIN2.oak on 2080 SBRKV4 Cross section xtabs2.oak XTABIN2.oek none Page 2 of 9 FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 2078 SBRKV2 Cross section Cross section xtabs2.oak XTABIN2.oak none 2077 SBRKVI xtabs2.oak XTABIN2.oak none none 2076 SW41ST Cross section xtabs2.oak XTABIN2.oak 1065 SSPIPU Cross section xtabsa UP.ext XTABSA.IN none none 1065 SSPIPD Cross section xtabsa UP.ext XTABSA.IN 2093 SW43RD Cross section xtabs2.oak XTABIN2.oak none 2092 SBRKW7 Cross section xtabs2.oak XTABIN2.oak none none 2091 SBRKW6 Cross section xtabs2.oak XTABIN2.oak 2090 SBRKW5 Cross section xtabs2.oak XTABIN2.oak _ none 2089 SBRKW4 Cross section xtabs2.oak XTABIN2.oak none none 2088 SBRKW3 Cross section xtabs2.oak XTABIN2.oak 2087 SBRKW2 Cross section xtabs2.oak XTABIN2.oak none 2086 SBRKWI Cross section xtabs2.oak XTABIN2.oak none 2085 SBRKWD Cross section xtabs2.oak XTABIN2.oak none none none none none none _ none none none none none none 1090 SBRKXU Cross section xtabsa UP.ext XTABSA.IN 1089 SW43RD Cross section xtabsa UP.ext XTABSA.IN 1091 SBRKYU Cross section xtabsa UP.ext XTABSA IN 1090 SBRKYD Cross section xtabsa UP.ext XTABSA.IN 1086 MILLCRKU Cross section xtabsa UP.ext XTABSA.IN 1085 MILLCRKD Cross section xtabsa UP.ext XTABSAIN 1302 SOCHNU Cross section xtabs.alt XTABINALT 1302 60CHND Cross section xtabs.alt XTABIN.ALT 1068 NSS80AU Cross section xtabsa UP.ext XTABSAIN 1068 NSS60AD Cross section xtabsa UP.ext XTABSA.IN 1066 S13PIPU Cross section xtabsa UP.ext XTABSA.IN 1066 S13PIPD Cross section xtabsa UP.ext XTABSA.IN none 1068 NSS60BU Cross section xtabsa UP.ext XTABSA.IN none 1068 NSS60BD Cross section xtabsa UP.ext XTABSA.IN none 1087 SR167-AU Cross section xtabsa UP.ext XTABSA.IN none 1087 SR167-AD Cross section xtabsa UP.ext XTABSA.IN none 1087 SR167-BU Cross section xtabsa UP.ext XTABSA.IN none 1087 SR167-BD Cross section xtabsa UP.ext XTABSA.IN none 1070 SS132U Cross section xtabsa UP.ext XTABSA.IN none 1070 SS132D Cross section xtabsa UP.ext XTABSA.IN none 1071 SS48U Cross section xtabsa UP.ext XTABSA.IN none 1071 SS48D Cross section xtabsa UP.ext XTABSA.IN none 8050 P9CHANU Cross section xtabsa UP.ext XTABINe2.txt none 8050 P9CHAND Cross section xtabsa UP.ext XTABINe2.txt none 8044 P9CHANAU Cross section pg.a2a HEC.P9 p92.hc2 8043 P9CHANAI Cross section p9.a2a HEC.P9 p92.hc2 8042 P9CHANA2 Cross section p9.a2a HEC.P9 p92.hr2 8041 P9CHANA3 Cross section p9.a2a HEC.P9 p92.hc2 8040 IPSICHABAD Cross section p9.a2a HEC.P9 p92.hc2 8046 P9CHANBU Cross section p9.a2a HEC.P9 p92.hc2 8045 P9CHANBD Cross section p9.a2a HEC.P9 p92.hc2 8045 P9CHANBU Cross section p9.a2a HEC.P9 p92.hc2 8045 P9CHANBD Cross section p9.a2a HEC.P9 p92.hc2 9008 P9CHAN Cross section xtabs.y2k XTABIN.Y2K none 9008 Cross section xtabs. 2k XTABIN.Y2K none 9013 P9CHAN Cross section xtabs.y2k XTABIN.Y2K none 9009 Cross section xtabs.y2k XTABIN.Y2K none 8049 P9CHANCU Cross section p9.a2a HEC.P9 p92.hc2 8048 P9CHANCI Cross section p9.a2a HEC.P9 p92.hc2 8047 P9CHANC2 Cross section p9.a2a HEC.P9 p92.hc2 8048 P9CHANCD Cross section 9.a2a HEC.P9 92.hc2 1074 SS60AU Cross section xtabsa UP.ext XTABSA.IN none Page 3 of 9 FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 1074 SS60AD Cross section xtabsa UP.ext XTABSA IN none 1067 S8PIPU Cross section xtabsa UP.ext XTABSA.IN none none none 1067 S8PIPD Cross section xtabsa UP.ext XTABSA.IN 1072 SS36U Cross section xtabsa UP.ext XTABSA.IN 1072 SS36D Cross section xtabsa UP.ext XTABSA.IN none 1081 PCRK-AU Cross section xtabsa UP.ext XTABSA.IN _ none 1081 PCRK-AD Cross section xtabsa UP.ext XTABSA.IN none none none none none none 1084 PCRK-BU Cross section xtabsa UP.ext XTABSA.IN 1084 PCRK-BD Cross section xtabsa UP.ext XTABSA.IN 1084 PCRK-CU Cross section xtabsa UP.ext XTABSA.IN 1084 PCRK-CD Cross section xtabsa UP.ext XTABSA.IN 8145 PSCHANU Cross section xtabrh UP XTABRH.IN 8144 Cross section xtabrh UP XTABRH.IN none 8143 Cross section xtabrh UP XTABRH.IN none 8142 Cross section xtabrh UP XTABRH.IN _ none 8146 Cross section xtabrh UP XTABRH.IN none 8141 Cross section xtabrh UP XTABRH.IN _ none 8141 P5CHAND Cross section xtabrh UP XTABRH.IN none 4026 BY405AU Cross section xtabs.703 XTABIN.703 none 4024 Cross section xtabs.703 XTABIN.703 none 4029 BY405AD Cross section xtabs.703 XTABIN.703 none 4028 BY405BD Cross section xtabs.703 XTABIN.703 none 2076 SW41STU Cross section xtabs2.oak XTABIN2.oak none 2076 SBCRK Cross section xtabs2.oak XTABIN2.oak none 2076 OAKU Cross section xtabs2.oak XTABIN2.oak none 100 Pump Operation Scenario 1 Pump Operation Pum tab.a none 695 Green River River levels vs time Green. m/Green.stor none 102 Pump Operation Scenario 2 Pump Operation Pum tab.a none 740 Pump Station foreba Stage/Storage Pondtabs.alt none Not used 500 Branch 1<> BRANCH 72 Expansion/contraction between branches xpcon e conin.txt xlabs.s /xtabs.703 501 Branch 1<> BRANCH 72 Expansion/contraction between branches oon expconin.txt xtabs.s /xlabs.703 324 IS16 OUTFLOW Ex ansior✓contraction Twodtabs.a twodina xtabsa u .ext/ 9.a2a/ 5.tab 326 S16 BACKFLOW ansion/contractlon Twodtabs.a twodina xtabsa u .ext/9 a2aAype5.tab 200 Grady Way Culvert table Grad u .tab Grad .btype5.tab/xtabs.7031xtabs.spg 202 Grady W Culvert table Gra u .tab Grad .btype5.tab/xtabs.703/Xtabs.spg 328 S15 OUTFLOW Ex ansion/contraction Twodtabs.a twodina xtabs/xtabsa up.exVpg.a2aftWe5.tab 330 S75 BACKFLOW Expansion/contraction Twodtabs.a twodina xtabs/xtabsa up.exVp9.a2aftype5.tab 602 Branch 9<> BRANCH 63 Expansion/contraction x con expconin.txt xtabs.s /xtabs.703 503 Branch 9<> BRANCH 63Expansion/contraction xpcon expconin.txt xtabs.s /xtabs.703 380 1-405 Culvert table 405culvert.out 405culvert.in type5.tab 381 1-405 Culvert table 405culvert.out 405culvert.in type5.tab 205 SW 16th Street bride Culvert table Twodtabs.16 twodin.16 e5.tab/b chan.tab/xtabs.l6 332 S14 OUTFLOW Expanslontcontraction Twodtabs.a twodina xtabs/xtabsa up.ext/p9.a2a4ype5.tab 334 S14 BACKLOW Expansion/contraction Twodtabs.a twodina xtabs/xtabsa up.ext/p9.a2aftype5.tab 750 Pond Area.forrP5 . ` Stage/Storage Pondtabs.alt none 208 After open chan. at end of 60 in SS. U to D Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.extlp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 210 After open than. at end of 60 in SS. U to D Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.exhdabrh u 900 Branch 37 <> Spring Brook Ex ansion/oontraction ITwodtabs u .Ist twodin.at 5.tab/xtabs.new/xtabs/xtabsa u .ext/xtabs.att 901 Branch 37 <> Spring Brook Expansion/contraction ITwodtabs u .1st 1twodin.1st e5.tab/xtabs.new/xtabs/xtabsa u .ext/xtabs.aft 212 Wetland 18 culvert Culvert table Twodtabs u .all twodin.alt XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u Page 4 of 9 FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments XTABS.ALT/xtabs2.301 ftype5.tab/xtabsa_up.ext/p9.a2a/xtabs2. 214 Wetland 1 B culvert Culvert table Twodtabs u .alt twodin.alt oak/xtabs2.extxtabrh u reference datum set high so not 216 Wetland 1A culvert Culvert table Twodtabs old.alt used in FEQ reference datum set high so not 218 1 Wetland 1A culvert Culvert table Twodtabs old.alt used not used in FEQ XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. 220 132 in SS inflow. Ex ansioNwntradion Twodtabs u .att twodin.aft oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. 222 132 in SS backfow ansion/contrection Twodtabs u .att twodin.alt oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. 224 48 in SS inflow. Expansion/contraction Twodtabs u .aft twodin.aft oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. 228 148 in SS backflow Ex ansiontcontraction Twodtabs u .aft twodin.aft oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. 228 P5 pond Embankment table Twodtabs u .aft twodin.aft oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. 230 P5 pond Embankment table Twodtabs u .alt twodin.alt oakhdabs2.ex/xtabrh u 701 Wetland lb Stage/Storage Pondtabs.alt none 700 Wetland 1a Stage/Storage Pondtabs.alt none XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. 232 SR187 3x4 Culvert table Twodtabs u .aft twodin.aft oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up. ext/p9.a2a/xtabs2. 234 SR167 3x4 Culvert table Twodtabs u .aft twodin.aft oakhdabs2.exhdabrh u XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. 320 Rubble weir d/s of 48" and 132" Embankment table Twodtabs u .aft twodin.alt oakhdabs2.ex/xtabrh u XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. 322 Rubble weir d/s of 48" and 132" Embankment table Twodtabs u .aft twodin.alt oakhdabs2.ex/xtabrth u 770 Wetland 12 Stage/Storage Pondtabs.alt none LONG PIPE FOR WETLAND 12- 36 INCH 352 WITH FLAP GATE Culvert table Twodtabs.a twodina xtabsa u .ext/9.a2 5.tab LONG PIPE FOR WETLAND 12- 38 INCH 354 WITH FLAP GATE - zero flow table Zero flow table Feg input file SHORT PIPE FOR WETLAND 12- 36 INCH NO 356 FLAP GATE Culvert table Twodtabs.a twodina xtabsa up.ext/p9.a2attype5.tab 345 P9 OUTFLOW Expensiontcontraction Twodtabs.a twodina xtabsa up.ext/pg.a2attype5.tab 347 P9 BACKFLOW Expansiontcontraction Twodtabs.a twodina xtabsa u .ext/ 9.a2a/ e5.tab XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. 236 Wetland 11a <> SR167 ditch Embankment table Twodtabs u .alt twodin.alt oak/xtabs2.ex/xtebrh u XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.exUp9.a2a/xtabs2. 238 Welland 11a <> SR167 ditch Embankment table Twodtabs u .alt twodin.alt oak/xtabs2.ex/xtabrh u 711 Wetland 11a Pondlabs.alt XTABS.ALThdabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. 240 Wetland 5 <> S rtn brook Embankment table Twodtabs u .aft twodin.alt oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. 242 Welland 5 <> S rin brook Embankment table Twodtabs u .att twodin.alt oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9. a2a/xtabs2. 244 wetland 4 <> S rin brook Embankment table Twodtabs u .alt twodin.alt oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301 ttype5.tab/xtabsa_up.ext/p9.a2a/xtabs2. 246 wetland 4 <> S rin brook Embankment table Twodtabs u .aft twodin.alt oak/xtabs2.ex/xtabrh u XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. 950 Drop above Linde Expansion/contraction Twodtabs u .aft twodin.alt oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301ttype5.tab/xtabsa up.ext/p9.a2a/xtabs2. 951 Drop above Linde Expansion/contraction Twodtabs u .aft twodin.alt oak/xtabs2.extxtabrh u XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up. ext/p9.a2a/xtabs2. 905 Two culverts on p9 at linde Culvert table Twodtabs u .aft 1twoclin.alt oak/xtabs2.extxtabrh u Page 5 of 9 FEQ Table Number Des ai tion Table T e FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 902 0 m is i ine u ated r as builts Au ust ulvert table Twodtabs u .1st twodin.at type5.tablxtabsa u .exthdabs.alt 903 Olympic pipeline updated per as builts August Culvert table Twodtabs u .Ist twodin.at 5.tab/xtabsa u .ext/xtabs.aft 248 Wetland 11a <> Wetland 11b Culvert table Twodtabs u .aft twodin.alt XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 705 Wetland 5 Stage/Storage Pondtabs.aft none 704 Welland 4 Stage/Storage Pondtabs.aft none 712 Wetland 11b Stage/Storage Pondtabs.alt none 703 Wetland 3 Stage/Storage Pondtabs.aft none 252 Bridge north of 27th Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.exbdabrh u 254 Bdd a north of 27th Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9. a2a/xtabs2. oak/xtabs2.ex/xtabrh u 256 Wetland 3 <> p9 channel Embankment table Twodtabs u .all twodin.alt XTABS.ALT/xtabs2.301/type5.tab/xtabsa_up.extlp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 258 Wetland 3 <> p9 channel Embankment table Twodtabs u .alt twodin.aft XTABS.ALT/xtabs2.301ttype5.tab/xtabsa up.exUp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 912 27th Street Culverts updated per as builts August 2002 Culvert table Twodtabs u .Ist twodin.at e5.tab/xtabsa u .ext/xtabs.alt 906 Control weir above new culvert under SR 167 Embankment table Twodtabs u .Ist twodin.at 5.tab/xtabsa up .exd/xtabs.att 908 Culvert under SR 167 Culvert table Twodtabs u .Ist twodin.at type5.tablxtabsa u .ext/xtabs.alt 909 Culvert under SR 187 Culvert table Twodtabs u .Ist twodin.at 5.tab/xtabsa u .exf/xtabs.alt 910 Culvert under E Valley Road Culvert table Twodtabs u .Ist twodin.at e5.tabadabsa u .exthdabs.alt 911 Culvert under E Valley Road Culvert table Twodtabs u .Ist twodin.lt typeS.tabtxtabsa u .ext/xtabs.aft 266 Wetland 6 <> Springbrook - not used by setting datum at 99.5 Embankment table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301/type5.tabadabsa_up.ext/p9.a2a/xtabs2. oaklxtabs2.exlxtabrh up Not used - set datum at 99.5 268 Wetland 6 <> Springbrook - not used by setting datum at 99.5 Embankment table Twodtabs u .att twodin.aft XTABS.ALT/xtabs2.301/type5.tabadabsa up.ext/p9.a2a/xtabs2. oakhdabs2.ex/xtabrh up Not used - set datum at 99.5 270 Panther Creek <> Wetland 11 Embankment table Twodtabs u .aft twodin.aft XTABS.ALT/xtabs2.301ttype5.tab/xtabsa up.extlp9.e2a/xtabs2. oakhttabs2.ex/xtabrh u 272 Panther Creek <> Wetland 11 Embankment table Twodtabs u .att twodin.alt XTABS.ALThdabs2.301 /lype5.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 7172 Welland 7b Stage/Storage Pondtabs.aft none 7073 Wetland 7c Stage/Storage Pondtabs.alt none 511 Wetland 7b <> 7c Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301 /types. tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 513 Wetland 7b <> 7c Culvert table Twodtabs u .aft twodin.alt XTABS.ALT/xtabs2.301/type5.tabadabsa_up.ext/p9.a2a/xtabs2. oakhdabs2.ex/xtabrh u 317 Wetland 7b to 7a Embankment table Twodtabs u .aft twodin.aft XTABS.ALThdabs2.301 /types.tab/Xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.extxtabrh-up commented out In FEQ. Not used 316 Wetland 7b to 7a Embankment table Twodtabs u .att twodin.aft XTAB S.ALThdabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh up commented out In FEQ. Not used 706 Wetland 6 Stage/Storage Pondtabs.aft none 302 Welland 8 <> S rin brook Embankment table Twodtabs u .att twodin.aft XTABS.ALT/xtabs2.301"5.tab/xtabsa up.ext/p9.a2andabs2. oak/xtabs2.ex/xtabrh u 304 Welland 8 <> S rin brook Embankment table Twodtabs u .aft twodin.aft XTAB S.ALT/xtabs2.301 /types.tabbdabsa_up.ext/p9.a2andabs2. oak/xtabs2.ex/xtabrh u 306 Wetland 9 <> S rin brook Embankment table Twodtabs u .aft twodin.aft XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2alxtabs2. oak/xtabs2.ex/xtabrh u 308 Wetland 9 <> S rin brook Embankment table Twodtabs u .att twodin.aft XTABS.ALT/xtabs2.301/type5.tab/xtabsa up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 274 Culvert 1 SR167 Panther Creek Culvert table Twodtabs u .att twodin.aft XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2andabs2. oak/xtabs2.ex/xtabrh u 276 Culvert 1 SR167 Panther Creek Culvert table Twodtabs u .aft twodin.aft XTAB SALT/xtabs2.301 /types.tab/Xtabsa_up.ext/p9.a2a/xtabs2. oakhdabs2.ex/xtabrh u 278 Culvert 2 SR167 Panther Creek Culvert table iTwodtabs u .att twodin.aft XTAB S.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2andabs2. oakhdabs2.exhdabrh u Page 6 of 9 FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 280 Culvert 2 SR167 Panther Creek Culvert table Twodtabs u .alt twodin.aft XTAB S.ALT/xtabs2.301 /types.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 709 Wetland 8 Stage/Storage Stage/Storage _ Pondtabs.alt none 708 Wetland 9 Pondtabs.alt none 348 SS60A <> SPRINGBROOKExpansion/contraction Twodtabs.a twodina xtabsa u .ext/9.a2a/ e5.tab 350 SS60A <> SPRINGBROOK Expansion/contraction Twodtabs.a twodina xtabsa u .ext/ 9.a2 5.tab 282 Panther Creek <> 36 Inch ss Expansion/contraction Twodtabs u .aft twodin.aft XTABS.ALT/xtabs2.301 /type5.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 284 Panther Creek <> 36 Inch ss Expansionlcontraction Twodtabs u .all twodin.alt XTABS.ALT/xtabs2.301 /types.tabadabsa_up.ext/p9.a2a/xtabs2. oakhdabs2.ex/xtabrh u 286 34th Street Culverts Culvert table Twodtabs u .alt twodin.aft XTABS.ALT/xtabs2.301Aype5.tab/xtabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.exhdabrh u 288 134th Street Culverts Culvert table Twodtabs u .aft twodin.alt XTABS.ALT/xtabs2.301Aype5.tab/xtabsa_up.extlp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 290 Wetland 10ab to S rin brook Embankment table Twodtabs u .aft twodin.aft XTABS.ALT/xtabs2.301Aype5.tab/xtabsa up.exVp9.a2a/xtabs2. oakhdabs2.exhdabrh u 710 Wetland 10 Sta a/Store a Pondtabs.alt none 292 Spring Brook to Wetland 10ab Embankment table Twodtabs u .alt twodin.aft XTABS.ALT/xtabs2.301 Aype5.tab/xtabsa_up.extlp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 318 Railroad Bride Culvert table Twodtabs.rr twodin.r e5.tab/xtabs2.301 336 S6 OUTFLOWExpansion/contraction Twodtabs.a twodina xtabsa up.exUp9.a2aAype6.tab 338 S6 BACKFLOWExpansion/contraction Twodtabs.a twodina xtabsa u .extt9.a2 S.tab 294 41st Street Culverts Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301 Aype5.tab/xtabsa_up.exVp9. a2a/xtabs2. oakhdabs2.exhdabrh u 296 41st Street Culverts Culvert table Twodtabs u .aft twodin.aft XTABS.ALThdabs2.301/typeS.tab/xtabsa_up.extlp9.a2andabs2. oak/xtabs2.ex/xtabrh u 607 Commented out. Not used 952 Weir flow over Oakesdale Embankment table Twodtabs.oak twodin.oak xtabs.alVxtabs2.oak 250 Upstream Oakesdale Culvert Culvert table Twodtabs.oak twodin.oak xtabs.altfxtabs2.oak 251 Upstream Oakesdale Culvert Culvert table Twodtabs.oak twodin.oak xtabs.alttxtabs2.oak 298 43rd Street culverts Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301Aype5.tab/xtabsa_up.exVp9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 300 43rd Street culverts Culvert table Twodtabs u .alt twodin.alt XTABS.ALT/xtabs2.301Aype5.tabadabsa_up.ext/p9.a2a/xtabs2. oak/xtabs2.ex/xtabrh u 340 MILL CREEK <> SPRINGBROOK Expansion/contraction Twodtabs.a twodina xtabsa u .ext/ 9.a2 e5.tab xtabsa up.ext/p9.a2aftype5.tab 342 MILL CREEK <> SPRINGBROOK I Expansion/contraction ITwodtabs.a twodina AQBmallve Inpun FEQ Table Number 2050 2051 2052 2053 2054 2055 2058 2057 2058 2059 2060 2061 2074 2078 2077 2078 2080 MA nU Descrt tion Table T FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments PSFORBYD Cross section FW2.out FWIN2.txt FWTAB3.lxt PSFORB10 Cross section FW2.out FWIN2.bd FWTAB3.bd PSFORM Cross section FW2.out FWIN2.txt FWTAB3.txt PSFORM Cross section FW2.out FWIN2.t)d FWTAB3.bd PSFORBY7 Cross section FW2.out FWIN2.txt FWTAB3.txt PSFORM Cross section FW2.out FWIN2.bd FWTAB3.bd PSFORM Cross section FW2.out FWIN2.txt FWTAB3.bd PSFORM Cross section FW2.out FWIN2.txt FWTAB3.txt PSFORM Cross section FW2.out FWIN2.txt FWTAB3.txt PSFORBY2 Cross section FW2.out FWIN2.txt FWTAB3.bd PSFORBYI Cross section FW2.out FWIN2.bd FWTAB3.txt PSFORM Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKCU Cross section FW2.out FWIN2.txt FWTAB3.txt SW41ST Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKVI Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKV2 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKV4 Cross section I FW2.out IFWIN2.txt FWTAB3.txt Page 7 of 9 FEQ Table Number 2081 2082 2083 2085 2086 2087 2088 2089 2090 2091 2092 2093 4010 4012 4014 4015 4016 4018 4019 4020 4021 4022 4025 4027 4028 9004 9005 9010 9012 9014 9021 9029 9030 9031 9032 9033 9035 9036 9039 9040 9043 9052 9053 9055 9056 9058 9065 9069 9071 9073 9075 9078 9079 9080 9082 9102 Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments SBRKVS Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKV6 Cross section FW2.out FWIN2.bd FWTAB3.txt SBRKV7 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKVU Cross section FW2.out FWIN2.bct FWTAB3.txt FWTAB3.bd SBRKWI Cross section FW2.out FWIN2.bd SBRKW2 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKW3 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKW4 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKWS Cross section FW2.out FWIN2.bct FWTAB3.txt SBRKW6 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKW7 Cross section FW2.out FWIN2.bct FWTAB3.bct SW43RD Cross section FW2.out FWIN2.bd FWTAB3.txt SBRKAD Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKAU Cross section FW2.out FWIN2.bd FWTAB3.txt SBRKB1 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKBU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKCI Cross section FW2.out FWIN2.bd _ FWTAB3.txt SBRKC2 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKC3 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKC4 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKDI Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKDU Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKEU Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKFD Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKDD Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKG3 Cross section FW2.out FWIN2.W FWTAB3.bd SBRKG2 Cross section FW2.out FWIN2.txt FWTA63.bd OAKBRD Cross section FW2.out FWIN2.bd FWTA83.txt OAKBRU Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKGI Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKGU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKH2 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKH3 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKH4 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKH5 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKH6 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKHU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRK11 Cross section FW2.out FWIN2.bct FWTAB3.bct SBRKI2 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKI3 Cross section FW2.out FWIN2.txt FWTAB3.bd HDBRID Cross section FW2.out FWIN2.bct FWTAB3.bd SBRK14 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRK15 Cross section FW2.out FWIN2.bd FWTAB3.txt SBRKIU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKJI Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKJ2 Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKJ3 Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKJ4 Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKJS Cross section FW2.out FWIN2.bd FWTAB3.txt SBRKJU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKKI Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKKU Cross section FW2.out IFWIN2.bd FWTAB3.txt SBRKLU Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKMI Cross section FW2.out FWIN2.txt FWTAB3.txt SBRKAD Cross section FW2.out FWIN2.txt FWTAB3.bd SIB Cross section FW2.out FWIN2.txt FWTA63.txt Page 8 of 9 w FEQ Table Number Description Table Type FEQUTL Output File FEQUTL Input File Input to FEQUTL Input File Comments 9103 9104 9105 9106 SBRKO2 Cross section FW2.out FWIN2.bct FWTAB3.txt SBRKOI Cross section FW2.out FWIN2.bd FWTAB3.bd FWTAB3.txt FWTAB3.bct SBRKPU Cross section FW2.out FWIN2.txt SBRKPU Cross section FW2.out FWIN2.bd 9107 SBRKQU Cross section FW2.out FWIN2.bct _ FWTAB3.bct 9108 9109 9110 9111 SW34TH Cross section FW2.out FWIN2.bd FWTAB3.bd SBRKSI Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKSU Cross section FW2.out FWIN2.txt FWTAB3.bd SBRKTI Cross section FW2.out FWIN2.bct FWTAB3.txt 9112 SBRKTU Cross section FW2.out FWIN2.bd FWTAB3.txt 9114 SW41ST Cross section FW2.out FWIN2.txt FWTAB3.bd 9115 SBRKUD Cross section FW2.out FWIN2.txt FWTAB3.txt 8040 P9CHABAD Cross section P9.FW HECFW.P9 P92FW.HC2 8041 P9CHANA3 Cross section P9.FW HECFW.P9 P92FW.HC2 8042 P9CHANA2 Cross section P9.FW HECFW.P9 P92FW.HC2 8043 P9CHANAI Cross section P9.FW HECFW.P9 P92FW.HC2 8044 P9CHANAU Cross section P9.FW HECFW.P9 P92FW.HC2 8045 P9CHANBD Cross section P9.FW HECFW.P9 P92FW.HC2 8046 P9CHANBU Cross section P9.FW HECFW.P9 P92FW.HC2 8046 P9CHANCD Cross section P9.FW HECFW.P9 P92FW.HC2 8047 P9CHANC2 Cross section P9.FW HECFW.P9 P92FW.HC2 8048 P9CHANCI Cross section P9.FW HECFW.P9 P92FW.HC2 8049 P9CHANCU Cross section P9.FW HECFW.P9 P92FW.HC2 700 Wetland 1a Stage/Storage Pondtabs.FW none 701 Wetland I Stage/Storage Pondtabs.FW none 703 Wetland 3 Stage/Storage Pondtabs.FW none 704 Wetland 4 Stage/Storage Pondtabs.FW none 7052 Wetland 5 Stage/Storage Pondtabs.FW none 7074 Wetland 7c Stage/Storage Pondtabs.FW none 708 Wetland 8 Stage/Storage Pondtabs.FW none 709 Wetland 9 Stage/Storage Pondtabs.FW none 710 Wetland 10 Stage/Storage Pondtabs.FW none 711 Wetland I I a Stage/Storage Pondtabs.FW none 712 1 Wetland 11b Stage/Storage Pondtabs.FW none 713 Wetland I I c Stage/Storage Pondtabs.FW none 740 Pump Station forebay Stage/Storage Pondtabs.FW none Not used 750 Pond Area for PS stage/Storage Pondtabs.FW none 7701 Wetland 12 Stage/Storage IPondtabs.FW none Page 9 of 9 Appendix D MEMORANDUM ENTITLED, "FEQ-HSPF VOLUME COMPARISON" (R. W. BECK, OCTOBER 28, 2005) TECHNICAL MEMORANDUM To: Allen Quynn, Project Manager, P.E., City of Renton Surface Water Utility Section From: Mary Weber, P.E./Mike Giseburt, P.E., R.W. Beck Subject: City of Renton — Springbrook Creek FEMA Remapping Study FEQ-HSPF Volume Comparison Date: October 28, 2005 Introduction The purpose of this memo is to present data to respond to questions related to the comparison of runoff volumes between FEQ and HSPF associated with the FEMA re -mapping of Springbrook Creek. This information was requested during a June 29, 2005 conference call that included the City of Renton, and representatives from R.W. Beck, nhc, FEMA Region X, Black and Veatch, and Michael Baker. The purpose of the comparison to was check for consistency between the two model simulations. The FEQ model is set up to route inflow hydrographs generated using the HSPF model. The volume comparison can be used to check that FEQ is indeed routing all the runoff volume. Note that that these are two independent models and there will be some differences between the two, however the difference should be relatively minor. Minor differences could be caused by differences in the way the models route flows in the system, HSPF has a groundwater component that may affect flow volumes. Analysis and Results The runoff volume comparison was done for the "conveyance" event and "storage" event. Data from the HSPF model was extracted from the WDM file for a location at the inflow to the BRPS' (DSN 297) for the February 8-9, 1996 (representing the "storage" event) and the January 9; 1990 event (representing the "conveyance" event). Data was entered into a spreadsheet to generate runoff volumes. The time period used for the calculations is noted below. Runoff volumes for FEQ were developed by requesting special hydrograph output data from at the forebay (downstream of Branch 72). This information was extracted for the same time period as noted above and entered into a spreadsheet to generate runoff volumes. Note that in order to make a direct volume comparison, it was necessary to apply a "Multiplier" that is used to scale up the hydrographs for FEQ modeling of events. This was done by simply multiplying the HSPF hydrograph flow rates by the same factors that are being used in FEQ for the 100-year event. The multipliers for these events are 1.13 for the "conveyance" event and 1.03 for the "storage event" (as described in nhc's hydrologic analysis). 11-00781-10000 1 001159 1 RASeattle\11-00781 Springbrook Creek FEMA remapping\Correspondence\files to Black & V ftp 10-28- 05\memo volume comparison 10-28-05.doc 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 TECHNICAL MEMORANDUM October 28, 2005 Page 2 The results are provided in the following table: Specific Time Runoff Volume (acre - Date of Period ft) Difference Difference Event Event From To FEQ HSPF acre-ft N Conveyance 1 /9/90 Jan 1 Jan 15 8,015 7,924 91 1.1 % Storage 2/9/96 Feb 1 Feb 15 6,147 6,001 146 2.4% The results are also presented in the attached two hydrographs. Note that for the "storage" simulation, the portion of the hydrograph that reflects zero flow is when the pump station is required to shut down when the Green River flows exceed 12,000. In both cases the runoff volume between FEQ and HSPF provides a good comparison, with FEQ having a slightly higher runoff volume. One of the potential reasons for FEQ having a slight higher volume is that all input hydrographs that are entering the system through branches such as pipes must have a non -zero value (i.e., pipes can't run dry or simulations stop). For these inflow hydrograph (particularly for the local basins that have less flow), FEQ has a minimum value (often 1 cfs). Overall, the comparison provides a good check for consistency and provides verification that all HSPF generated runoff volume is accounted for in the hydraulic analysis. 1001 Fourth Avenue, Suite 2500 Seattle, WA 98154-1004, Phone (206) 695-4700, Fax (206) 695-4701 1400 1200 1000 ,. 800 N _o LL 600 Forebay Hydrograph - Conveyance Scenario 200 250 300 350 400 Hours -�- FEQ -f- HSPF 1800 1600 1400 1200 1000 w 3 0 M 800 600 400 200 0 Forebay Hydrograp h-Storage Scenario 0 100 200 300 400 500 600 Hours —+— FEQ HSPF All f r � r f 1, � r / ,% - mr, • At -..,�klll�lltlilllllll�lliil►Cttl\�sa�x�l�r�itu��w..,.....�-�� k ti -fa h ` ,off+r..`.'•-'.✓�svMO �'% 'W7 z k. _E e III V�ir`�--= _ y 1_� _ : ... i '.r .yam ! _ -.- - ,_ -,-'--'-•.`d :-- T - - MMO 0L 0 an 0 Cl) LL I W L � O LM a ti C� 00 ti 00 00 O CO M lO . . O � N U O E cu E (n ° U U � � L.L U_ Nuul r. j '^ .. , .1 MS 3AV aavH —___ — _ - � f . p- � CO r s -- — - — G�� AMH DIVA 1 V3 % ° 4-j v _�� r`� [�a 1 Q� �1 4 e J� o {f o ` _ 4� V — — O .. r— O ' O O 0 0 Q O `�--� j d i ►� / ``, V` ° �e��� Q ' 0�' [ cco eo I 0 0 n �l o o 0 (� ' GJ "j r I'*-- y m O (> j f . I ( >, O C j �z _' e o r W�Q W 11 O t� c ° U '^ U $ : o�` x a°i aUi + I ; 4 p r ; ° r ^, > Li J ns _ v u J W T s -a to p l O U Y J d1 I W `, Q ® V J V _s t O o tY �- »- `` e o N a t\ \ �/ O ; ai c 1 4 i j 1 Z a 0 C� �_�.J �' - V I G••7/1Lr or 1> r�. V e 1 119 { z O .� r d I Q a e V W _.,v 3>dprY j L�_A�� �` �° ® (e d ° �. N/—�� p cn }� O Q O O Q N 11_:? 4 MS 3Ad ONII K� ?r ® c"r'-' -,r o V " o p o j - " a- 0 G � - I", ,7)-,, t - L y -\ ---\, � A S, .- --a 0 t ' O cn UN^.v� L �l'----'''---•---r O O 0 U j a : o !.-"\ D G yU �+S 1 d co U to O � \ Q � � � j 1 e %u � Q O . �10 l J ) rri o ii a c •- ar- ° / e O 0 1; x 1 °� Ci c '`' r Q a r N o f Qi a _ {o O (o I O rn c 3 �.; cn � M e 0 c ° co — - o iU / ,-- o O �, d rn MS 3Ad aNdWA + r n 1, IR1 LL cwi c Z a) o a� o_ Ow e .o o "O- C; 2 V O - 1 Z I I N e Q M A _' - { L\ r o O (L6y\ \ e D ca 18` ti I �l 1 �� t i �y1 io X 1 0 t \\ s �N m O c I' O O p U �� �• vv Q U •O U= o t \\ `�` e- ' O O C — H, C ry C = a) � r \ \ . ♦� C U '�j 7 ch tII O ~ U Y O N 0) tB () W \ / / x ,O \ \ a3 C 0) U O •- > ' �1 y a c x /, Q coi t.! O ----_ v� \\ 3 - c N a) E c c .� o 01 �l m c N c xe m e c Q /X _ (� N -. ff \} o. / w L _ o � 3 O Lo L >, ao' uw1: L f f x v ch v m ( E�w U m U) 0a) c*= o U 3 tf o U r/ N O J ¢ i 3 cn - \\ !I Q' c� c t o � - CD a) t O fn O 1 I . to i� D w C C co (0 �i% \\ \ d o o G O fl I (6 0 p- N L j OU V 0 _ Q .� r.+ U Q �' •0 Qi d - I 1 l W o { .� ..\ \ �`3 • L - E Q 7 CL `Ja ca o c--� cv o o w v / u m �. U U. ed {j \ t m- I to c nn MS 3AV �d `` r > �, / d o o �, ' m" ,00n�{{'CD v.� �oE w �'i� w Q 0 3� ��U `1 ��\ •� �n�ca3c>'o `� c rn>LL 30oc��L c° 4 _ 1f4l,,r I L o 03 m i� L m a _ o Vi �� \ \\ cO N> 0 0 0 0 3 f ,YVIt / J O - -_-_/ - v �c�,� �tiln Z �Oas� / p o o �' - \\, "� o °Oc3 �.' - nQo3 �� mW 3 n o 0y . O \ v —;f O t / N a U C cn otS L!i p 0) i� — rN, ` f U i 1 Z f- 0) r' \ r w N �_ ' l� U to O to + _ t� , 0 N l \ \ U e C > O C \ \\\ O t0 tp, e U O (U6 J Z t� Q O N O N Z v f Q ' O - \\\ / C / / VVV 3 .t : • J - O c 3: g \ \ L N O U- I , J c6 _ v� ' L c O N" r r %. ' i 4�\'\� 0) 1!! V� !� Z O ci% O V- O Q> 1+�+, O rn o `'. �.. O a • • ._ — °. _ ���/ -:' �"'./ O 4. \. J Q N` O O ° rL+ a) v, r L CJ N a''� �' . a N c �T _- b Z -o \ ti I ao m e = L" U >' O O U ^/ \� 1'; o C e O ch -_ O N U c= O 0) _ (� _ i (D N .1 ( O :. /� / ''j i� O - "'�'.,�- to -.�_.. _ r l `'\ o n !"_l o._./: /1 O G. - \�.1 l t0 L O V RS O O O O W U O N a) j c o �c tj ,; c \\ ( E o MS'�AV 31 d0 �M8�3IF11�11� ov p >, � ° ° o ( o c° j / /:'• t< . m f c o c� ,t,GO \\ = : _ , i ` _ U c c a>i -c' � � c� m Z ❑ C! U- Q a) N V t OL V 1- (� O N >� N r E U Q X p Cn �p N O cn w a) ea a) " L m a) I o c a� o_ .� N� U :E _O ✓ ~ N to O O I e to C O t� �i \ \ ❑ LL -- .Cn LL E O ._ N U) N -- ��� CpS��dO U Q o c D Q = c. Co 0 v� `� ; m` o rOa A ( oQ L c ° a N 1 tt o�� M } \ - cn Jv ` } N .. C -O Y \ \ a w e l„�� A O_ Z o �' -+ >. © 0 3 N 3 co a) -� o- c cv D 0 cfl No g O > ��' f- v Q c' cif 1 a 1 1 ►� a) cn C N o t 1 1 (D LO o m • fl > U S ` ;C 'C N N Ua) �7AR a 4i 0) 4 $ O C +r > - C\ r Nl O N N N r� (� � O ((>�✓ ; I 1 W N N O \ V C y t > O-.0 Ip — +, . ' - Q `J �. 3 N fl. u) r` ►/ 1 / "! o O- L O m U rn N o .t✓ E �' �': O— t c n: o ° as cTf o 1 1\ `' ' co e`i C9 a) a i w e O o e) li o ° o o L - 0 bc�� 1 �m Ha�� C ( Qc �'. U�o� k� Z��OEo $ tom' 4 ioc k� E ca ; c O 1 o C c{ J/ p 0 e a o` \\ \ c LZ I, �. fl. •O �- \ ',:, `. \\ I / a..e N y � \' c0 '7 N W jJ(J � Z � (J�) • \ \ � � cn N Q Q) Lr) 00 �\� - O\\ \\ N �_EX F- E r X_ 8 a -f - -_ O (0 +t N o UU `\ " ° �-- -� , n n e o v �v ,� , � � m -- � �L � - 1 c w �• � e ° C �' � -o� •"�-�, / � - /e�Yuual u{ea aapunos _ p - ns c I - -- _ \ f a� - _,-_, . f . (1 — . ITY OF REN ON Y _ 31 6 65 Z a)0- °.- -r- (1) -,(� It (1) S 0>,0ma)0 - I� -O0 'U > p "O +ED O � U N � ---� --__ - U ai�mUm�U e, • I f / %� d f/I/•J � �-- - L` ~,,. e� e-•� ����-p,L`� :�=�=��—`'`s`',�'s�.`� _-ems"".",.- � .1 � E � -gyp F_ \ tt _ - •Qua' o o a pw F'a-, N 3 c c cn inL a) Q o Q O O (YO Cn Off- a) (n I j e t4i� c E 00 O c voi o >= L y eo c o -0 o s > o cn o 0 % E-c , CS co `� o c c vcni cow c° aci t ti N LSO o o a) a) -_ 0 a) a) O O' _ _ - f' Gr j' , ��� .tee CI -^ U 6 0 . �. 0 D '�' S• (� a>+ .O �+ hh �•ID U 60 k ' \ _ N V C L U L O p U o 0 - a) � ai � c � � � � 0 ai _N)�, I(1) _ c, vUi c x r) c U U) C(U) U) 0 �� Y ,.� O O d O O N a) c ' 0 O a ° r - - o ❑ loi m E O to cA M L) � - cn r 'v 2T ca n — _ 1� r" CD LO i {r r `L: n N i •I o � W 7 ✓ 1 v 0 I C7 o N 1: - y o .J MC L ! c� J j d H10 a) 0 C �' 0� a .0 LO 00 - 00 co O cv N W Z I �p m co 0, (n � r m co co C) _� V) p O O L O Q Q Q N ���° - 80) U a) 0 c c c cn a) w— 06 Z- o- E c O_ 0) a) co c m Z C) '� a) �_ ca o a) ca o cu Y U U O C U m> O U L = 0 o 3 0 0 a �L3 �acaa)()m -0 E Z U O 0 U -O 0) >+ — a) • O 3 t 4) 3 3 r0_ p)o Q❑ m C 0( L 00 N O - >' N CO O • C V) (6 c O p) O 'C a) p ¢ �y i N c W N �' O N 2E-• �' c >N • D` N m N O O N E a) 'C N O = O-a N >, 0) 00 c0 0 O C 3 O c a)� c m UTrn a) c N L N o ~ U O 00 D_ U 0) v) y a) C O "- >+ c— N 0 c ?,a c - m v o o❑ (� o o o o- o {, 0 0•� o m u n oa-0Q p �Ja'a)a) �a��i�a-�i�� >�Za��i 0 % a) � 0 co o m ° 0 ° o e a) H ° I- ° r co 3 0 >, >, o 0 N ca ca0 — c D W L L 0 0) 0) °- c- L o 1 c C C o 0 0) O O 0 > N N J ° M a? � C Y � � L o U m m � c O C U C U i c0 Q > ai - L U a) c o W o O Y .>0a O a) Xcu o 0 cu c6 >� - -0 "0 cc a) ° o -°o m o ° ° o o a � °) LL m N N U U Q a- w c � � 1 j e j 1 I J